Covalent modification of metal surfaces

ABSTRACT

The present invention provides modified metal surfaces, methods of preparing the same, and intermediates thereto. These materials are useful in a variety of applications including biomaterials.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional patent applicationSer. No. 60/819,200, filed Jul. 7, 2006, the entirety of which is herebyincorporated herein by reference.

BACKGROUND OF THE INVENTION

Modification of inorganic substrates with polymeric materials has beenutilized in a range of applications across numerous scientificdisciplines including analytical chemistry, biology, and electronics.(Mansky, P., et al. Science 1997, 275, 1458-1460; Huang, Z. Langmuir,1997, 13, 6480-6484. Granick, S. et. al. J. Polym. Sci. B. 2003, 41,2755-2793.) Inorganic substrates can be coated with polymers or othermolecules using a number of currently available methods. One popular,simple method involves the physical adsorbtion of a polymer to asubstrate through coating or other deposition techniques. Other methodsutilize covalent or ionic bonding between functionality on a polymer, orsmall molecule, and functionality present on the substrate surface toachieve modification. (Denes, A. R. et. al. J. Appl. Polym. Sci. 2001,81, 3425-3438). While simple adsorption of polymers to metal substrateshas proven successful in many cases, this procedure does not producemechanically robust coatings with long-term stability. Post-adsorptioncrosslinking (Dong, B. et. al.; J. Appl. Polym. Sci., 2005, 97,485-497.) of the polymer coating may increase the toughness andshort-term performance of the resulting film, but such crosslinking canalso result in cracking and flaking of the polymer films over time,resulting in mechanical failure and a dramatic reduction in filmproperties. The chemical attachment of functional polymers to a metalsubstrate introduces a stable, robust linkage between polymer chains andthe metal substrate and represents a more desirable scenario for manyapplications where the long-term stability of the coating is requiredfor optimal performance. (Hara, H. et. al. Adv. Drug Del. Rev. 2006, 58,377-388.) However, the methodologies to prepare covalent attachment ofpolymers to metallic and non-metallic substrates has thus far beenlimited to only a few examples of suitable substrates and complimentarychemical functionalities. Such examples include the near-covalentinteraction between gold substrates and thiol-functionalized molecules,covalent bonds formed between silica and alcohol, silyl chloride, orsilyl alcohol-functionalized compounds, and covalent bonds formedbetween hydrogen-functionalized silicon surfaces and alkene-substitutedmolecules. (Mansky, P., et. al. Science 1997, 275, 1458-1460, Pesek, J.J.; Matyska, M. T. Interface Science 1997, 5, 103-117.)

Accordingly, it would be advantageous to provide a method of modifyingmetal surfaces to provide a metal substrate capable of forming covalentbonds with appropriately functionalized polymers or small moleculederivatives.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a method for covalently modifying a metal surface viadehydration reaction.

FIG. 2 depicts a method for covalently modifying a metal surface viacondensation reaction.

FIG. 3 depicts a method for covalently modifying a metal surface viadehydration reaction.

FIG. 4 depicts a method for covalently modifying a metal surface viacondensation reaction.

FIG. 5 depicts a method for covalently modifying a metal surface viadehydration reaction.

FIG. 6 depicts a method for covalently modifying a metal surface viacondensation reaction.

FIG. 7 depicts a method for covalently modifying a metal surface viadehydration reaction.

FIG. 8 depicts a method for covalently modifying a metal surface viacondensation reaction.

FIG. 9 depicts a method for covalently modifying a metal surface andcrosslinking via dehydration reaction.

FIG. 10 depicts a method for covalently modifying a metal surface viacondensation reaction followed by crosslinking.

FIG. 11 depicts a method for PEGylating a metal surface via dehydrationreaction.

FIG. 12 depicts a method for PEGylating a metal surface via condensationreaction.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE INVENTION 1. GeneralDescription of the Invention

The present invention provides methods for covalently modifying a metalsurface with a polymeric group or a small molecule organic moiety. Inorder to covalently bond the polymeric group or small molecule organicmoiety to the metal surface, the metal surface is treated to introducehydroxyl groups. In certain embodiments, the present invention providesa method for covalently modifying a metal surface, comprising the stepsof introducing hydroxyl groups onto a metal substrate and covalentlybonding a polymer or small molecule organic moiety onto the resultinghydrophilic metal surface.

2. Definitions

Compounds of this invention include those described generally above, andare further illustrated by the embodiments, sub-embodiments, and speciesdisclosed herein. As used herein, the following definitions shall applyunless otherwise indicated. For purposes of this invention, the chemicalelements are identified in accordance with the Periodic Table of theElements, CAS version, Handbook of Chemistry and Physics, 75^(th) Ed.Additionally, general principles of organic chemistry are described in“Organic Chemistry”, Thomas Sorrell, University Science Books,Sausalito: 1999, and “March's Advanced Organic Chemistry”, 5^(th) Ed.,Ed.: Smith, M. B. and March, J., John Wiley & Sons, New York: 2001, theentire contents of which are hereby incorporated by reference.

As used herein, the term “sequential polymerization”, and variationsthereof, refers to the method where after a first monomer (e.g. NCA orlactam) is incorporated into the polymer, thus forming a “block”, asecond monomer (e.g. NCA or lactam) is added to the reaction and thepolymerization continues in a similar fashion resulting in the formationof multi-block copolymers.

As used herein, the term “block copolymer” refers to a polymercomprising two or more polymer portions. The term “multi-blockcopolymer” refers to a polymer comprising at least three separatepolymer portions. These are also referred to as triblock copolymers,tetrablock copolymers, etc. Such multi-block copolymers may be of theformat X-W-X′, W-X-X′, W-X-X′-X″ or X′-X-W-X-X′, wherein W is a certainsynthetic polymer portion and X, X′, and X″ are differing polymerchains. In certain aspects, the synthetic polymer is used as the centerblock which allows the growth of multiple blocks symmetrically fromcenter.

As used herein, the term “synthetic polymer” refers to a polymer that iswell known in the art and includes polystryrene, polyalkylene oxides,polyacrylates, polyacrylamides, polyamines, polyolefins, and derivativesthereof.

As used herein, the term “natural polymer” refers to a polymer that iswell known in the art and includes polysaccarides, dextran, heparin,fibronectin, poly(amino acids), starch, amylose, amylopectin,polypeptides, proteins, and derivatives thereof.

As used herein, the term “polymer” may refer to either a natural polymeror synthetic polymer.

As used herein, the term “poly(amino acid)” or “amino acid block” refersto a covalently linked amino acid chain wherein each monomer is an aminoacid unit. Such amino acid units include natural and unnatural aminoacids. In certain embodiments, each amino acid unit is in theL-configuration. Such poly(amino acids) include those having suitablyprotected functional groups. For example, amino acid monomers may havehydroxyl or amino moieties which are optionally protected by a suitablehydroxyl protecting group or a suitable amine protecting group, asappropriate. Such suitable hydroxyl protecting groups and suitable amineprotecting groups are described in more detail herein, infra. As usedherein, an amino acid block comprises one or more monomers or a set oftwo or more monomers. In certain embodiments, an amino acid blockcomprises one or more monomers such that the overall block ishydrophilic. In other embodiments, an amino acid block comprises one ormore monomers such that the overall block is hydrophobic. In still otherembodiments, amino acid blocks of the present invention include randomamino acid blocks, ie blocks comprising a mixture of amino acidresidues.

As used herein, the phrase “natural amino acid side-chain group” refersto the side-chain group of any of the 20 amino acids naturally occurringin proteins. Such natural amino acids include the nonpolar, orhydrophobic amino acids, glycine, alanine, valine, leucine isoleucine,methionine, phenylalanine, tryptophan, and proline. Cysteine issometimes classified as nonpolar or hydrophobic and other times aspolar. Natural amino acids also include polar, or hydrophilic aminoacids, such as tyrosine, serine, threonine, aspartic acid (also known asaspartate, when charged), glutamic acid (also known as glutamate, whencharged), asparagine, and glutamine. Certain polar, or hydrophilic,amino acids have charged side-chains. Such charged amino acids includelysine, arginine, and histidine. One of ordinary skill in the art wouldrecognize that protection of a polar or hydrophilic amino acidside-chain can render that amino acid nonpolar. For example, a suitablyprotected tyrosine hydroxyl group can render that tyrosine nonpolar andhydrophobic by virtue of protecting the hydroxyl group.

As used herein, the phrase “unnatural amino acid side-chain group”refers to amino acids not included in the list of 20 amino acidsnaturally occurring in proteins, as described above. Such amino acidsinclude the D-isomer of any of the 20 naturally occurring amino acids.Unnatural amino acids also include homoserine, ornithine, and thyroxine.Other unnatural amino acids side-chains are well know to one of ordinaryskill in the art and include unnatural aliphatic side chains. Otherunnatural amino acids include modified amino acids, including those thatare N-alkylated, cyclized, phosphorylated, acetylated, amidated,azidylated, labelled, and the like.

As used herein, the phrase “living polymer chain-end” refers to theterminus resulting from a polymerization reaction having maintainedchain-end reactivity after the completion of the reaction.

As used herein, the term “termination” refers to attaching a terminalgroup to a polymer chain-end by the reaction of a living polymer with anappropriate compound. Alternatively, the term “termination” may refer toattaching a terminal group to a hydroxyl end, or derivative thereof, ofthe polymer chain.

As used herein, the term “polymerization terminator” is usedinterchangeably with the term “polymerization terminating agent” andrefers to a compound for attaching a terminal group to a polymerchain-end of a living polymer. Alternatively, the term “polymerizationterminator” may refer to a compound for attaching a terminal group to ahydroxyl end, or derivative thereof, of the polymer chain.

As used herein, the term “polymerization initiator” refers to acompound, or anion thereof, which reacts with the desired monomer in amanner which results in polymerization of that monomer. In certainembodiments, the polymerization initiator is the anion of a functionalgroup which initiates the polymerization of ethylene oxide. In otherembodiments, the polymerization initiator is the amine salt describedherein.

As described herein, compounds of the invention may optionally besubstituted with one or more substituents, such as are illustratedgenerally above, or as exemplified by particular classes, subclasses,and species of the invention. It will be appreciated that the phrase“optionally substituted” is used interchangeably with the phrase“substituted or unsubstituted.” In general, the term “substituted”,whether preceded by the term “optionally” or not, refers to thereplacement of hydrogen radicals in a given structure with the radicalof a specified substituent. Unless otherwise indicated, an optionallysubstituted group may have a substituent at each substitutable positionof the group, and when more than one position in any given structure maybe substituted with more than one substituent selected from a specifiedgroup, the substituent may be either the same or different at everyposition. Combinations of substituents envisioned by this invention arepreferably those that result in the formation of stable or chemicallyfeasible compounds.

The term “stable”, as used herein, refers to compounds that are notsubstantially altered when subjected to conditions to allow for theirproduction, detection, and preferably their recovery, purification, anduse for one or more of the purposes disclosed herein. In someembodiments, a stable compound or chemically feasible compound is onethat is not substantially altered when kept at a temperature of 40° C.or less, in the absence of moisture or other chemically reactiveconditions, for at least a week.

The term “aliphatic” or “aliphatic group”, as used herein, means astraight-chain (i.e., unbranched) or branched, substituted orunsubstituted hydrocarbon chain that is completely saturated or thatcontains one or more units of unsaturation, or a monocyclic hydrocarbonor bicyclic hydrocarbon that is completely saturated or that containsone or more units of unsaturation, but which is not aromatic (alsoreferred to herein as “carbocycle” “cycloaliphatic” or “cycloalkyl”),that has a single point of attachment to the rest of the molecule.Unless otherwise specified, aliphatic groups contain 1-20 aliphaticcarbon atoms. In some embodiments, aliphatic groups contain 1-10aliphatic carbon atoms. In other embodiments, aliphatic groups contain1-8 aliphatic carbon atoms. In still other embodiments, aliphatic groupscontain 1-6 aliphatic carbon atoms, and in yet other embodimentsaliphatic groups contain 1-4 aliphatic carbon atoms. In someembodiments, “cycloaliphatic” (or “carbocycle” or “cycloalkyl”) refersto a monocyclic C₃-C₈ hydrocarbon or bicyclic C₈-C₁₂ hydrocarbon that iscompletely saturated or that contains one or more units of unsaturation,but which is not aromatic, that has a single point of attachment to therest of the molecule wherein any individual ring in said bicyclic ringsystem has 3-7 members. Suitable aliphatic groups include, but are notlimited to, linear or branched, substituted or unsubstituted alkyl,alkenyl, alkynyl groups and hybrids thereof such as (cycloalkyl)alkyl,(cycloalkenyl)alkyl or (cycloalkyl)alkenyl.

The term “heterocycle”, “heterocyclyl”, “heterocycloaliphatic”, or“heterocyclic” as used herein means non-aromatic, monocyclic, bicyclic,or tricyclic ring systems in which one or more ring members is anindependently selected heteroatom. In some embodiments, the“heterocycle”, “heterocyclyl”, “heterocycloaliphatic”, or “heterocyclic”group has three to fourteen ring members in which one or more ringmembers is a heteroatom independently selected from oxygen, sulfur,nitrogen, or phosphorus, and each ring in the system contains 3 to 7ring members.

The term “heteroatom” means one or more of oxygen, sulfur, nitrogen,phosphorus, or silicon (including, any oxidized form of nitrogen,sulfur, phosphorus, or silicon; the quaternized form of any basicnitrogen or; a substitutable nitrogen of a heterocyclic ring, forexample N (as in 3,4-dihydro-2H-pyrrolyl), NH (as in pyrrolidinyl) orNR⁺ (as in N-substituted pyrrolidinyl).

The term “unsaturated”, as used herein, means that a moiety has one ormore units of unsaturation.

The term “alkoxy”, or “thioalkyl”, as used herein, refers to an alkylgroup, as previously defined, attached to the principal carbon chainthrough an oxygen (“alkoxy”) or sulfur (“thioalkyl”) atom.

The terms “haloalkyl”, “haloalkenyl” and “haloalkoxy” means alkyl,alkenyl or alkoxy, as the case may be, substituted with one or morehalogen atoms. The term “halogen” means F, Cl, Br, or I.

The term “aryl” used alone or as part of a larger moiety as in“aralkyl”, “aralkoxy”, or “aryloxyalkyl”, refers to monocyclic,bicyclic, and tricyclic ring systems having a total of five to fourteenring members, wherein at least one ring in the system is aromatic andwherein each ring in the system contains 3 to 7 ring members. The term“aryl” may be used interchangeably with the term “aryl ring”. The term“aryl” also refers to heteroaryl ring systems as defined hereinbelow.

The term “heteroaryl”, used alone or as part of a larger moiety as in“heteroaralkyl” or “heteroarylalkoxy”, refers to monocyclic, bicyclic,and tricyclic ring systems having a total of five to fourteen ringmembers, wherein at least one ring in the system is aromatic, at leastone ring in the system contains one or more heteroatoms, and whereineach ring in the system contains 3 to 7 ring members. The term“heteroaryl” may be used interchangeably with the term “heteroaryl ring”or the term “heteroaromatic”.

An aryl (including aralkyl, aralkoxy, aryloxyalkyl and the like) orheteroaryl (including heteroaralkyl and heteroarylalkoxy and the like)group may contain one or more substituents. Suitable substituents on theunsaturated carbon atom of an aryl or heteroaryl group are selected fromhalogen; N₃, CN, R^(o); OR^(o); SR^(o); 1,2-methylene-dioxy;1,2-ethylenedioxy; phenyl (Ph) optionally substituted with R^(o); —O(Ph)optionally substituted with R^(o); (CH₂)₁₋₂(Ph), optionally substitutedwith R^(o); CH═CH(Ph), optionally substituted with R^(o); NO₂; CN;N(R^(o))₂; NR^(o)C(O)R^(o); NR^(o)C(O)N(R^(o))₂; NR^(o)CO₂R^(o);—NR^(o)NR^(o)C(O)R^(o); NR^(o)NR^(o)C(O)N(R^(o))₂; NR^(o)NR^(o)CO₂R^(o);C(O)C(O)R^(o); C(O)CH₂C(O)R^(o); CO₂R^(o); C(O)R^(o); C(O)N(R^(o))₂;OC(O)N(R^(o))₂; S(O)₂R^(o); SO₂N(R^(o))₂; S(O)R^(o); NR^(o)SO₂N(R^(o))₂;NR^(o)SO₂R^(o); C(═S)N(R^(o))₂; C(═NH)—N(R^(o))₂; or (CH₂)₀₋₂NHC(O)R^(o)wherein each independent occurrence of R^(o) is selected from hydrogen,optionally substituted C₁₋₆ aliphatic, an unsubstituted 5-6 memberedheteroaryl or heterocyclic ring, phenyl, O(Ph), or CH₂(Ph), or,notwithstanding the definition above, two independent occurrences ofR^(o), on the same substituent or different substituents, taken togetherwith the atom(s) to which each R^(o) group is bound, form a 3-8 memberedcycloalkyl, heterocyclyl, aryl, or heteroaryl ring having 0-4heteroatoms independently selected from nitrogen, oxygen, or sulfur.Optional substituents on the aliphatic group of R^(o) are selected fromN₃, CN, NH₂, NH(C₁₋₄aliphatic), N(C₁₋₄aliphatic)₂, halogen,C₁₋₄aliphatic, OH, O(C₁₋₄aliphatic), NO₂, CN, CO₂H, CO₂(C₁₋₄aliphatic),O(haloC₁₋₄aliphatic), or haloC₁₋₄aliphatic, wherein each of theforegoing C₁₋₄aliphatic groups of R^(o) is unsubstituted.

An aliphatic or heteroaliphatic group or a non-aromatic heterocyclicring may contain one or more substituents. Suitable substituents on thesaturated carbon of an aliphatic or heteroaliphatic group, or of anon-aromatic heterocyclic ring are selected from those listed above forthe unsaturated carbon of an aryl or heteroaryl group and additionallyinclude the following: ═O, ═S, ═NNHR*, ═NN(R*)₂, ═NNHC(O)R*,═NNHCO₂(alkyl), ═NNHSO₂(alkyl), or ═NR*, where each R* is independentlyselected from hydrogen or an optionally substituted C₁₋₆ aliphatic.Optional substituents on the aliphatic group of R* are selected fromNH₂, NH(C₁₋₄ aliphatic), N(C₁₋₄ aliphatic)₂, halogen, C₁₋₄ aliphatic,OH, O(C₁₋₄ aliphatic), NO₂, CN, CO₂H, CO₂(C₁₋₄ aliphatic), O(halo C₁₋₄aliphatic), or halo(C₁₋₄ aliphatic), wherein each of the foregoingC₁₋₄aliphatic groups of R* is unsubstituted.

Optional substituents on the nitrogen of a non-aromatic heterocyclicring are selected from R⁺, N(R⁺)₂, C(O)R⁺, CO₂R⁺, C(O)C(O)R⁺,C(O)CH₂C(O)R⁺, SO₂R⁺, SO₂N(R⁺)₂, C(═S)N(R⁺)₂, C(═NH)—N(R⁺)₂, orNR⁺SO₂R⁺; wherein R⁺ is hydrogen, an optionally substituted C₁₋₆aliphatic, optionally substituted phenyl, optionally substituted O(Ph),optionally substituted CH₂(Ph), optionally substituted (CH₂)₁₋₂(Ph);optionally substituted CH═CH(Ph); or an unsubstituted 5-6 memberedheteroaryl or heterocyclic ring having one to four heteroatomsindependently selected from oxygen, nitrogen, or sulfur, or,notwithstanding the definition above, two independent occurrences of R⁺,on the same substituent or different substituents, taken together withthe atom(s) to which each R⁺ group is bound, form a 3-8-memberedcycloalkyl, heterocyclyl, aryl, or heteroaryl ring having 0-4heteroatoms independently selected from nitrogen, oxygen, or sulfur.Optional substituents on the aliphatic group or the phenyl ring of R⁺are selected from NH₂, NH(C₁₋₄ aliphatic), N(C₁₋₄ aliphatic)₂, halogen,C₁₋₄ aliphatic, OH, O(C₁₋₄ aliphatic), NO₂, CN, CO₂H, CO₂(C₁₋₄aliphatic), O(halo C₁₋₄ aliphatic), or halo(C₁₋₄ aliphatic), whereineach of the foregoing C₁₋₄aliphatic groups of R⁺ is unsubstituted.

As detailed above, in some embodiments, two independent occurrences ofR^(o) (or R⁺, or any other variable similarly defined herein), are takentogether with the atom(s) to which each variable is bound to form a3-8-membered cycloalkyl, heterocyclyl, aryl, or heteroaryl ring having0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.Exemplary rings that are formed when two independent occurrences ofR^(o) (or R⁺, or any other variable similarly defined herein) are takentogether with the atom(s) to which each variable is bound include, butare not limited to the following: a) two independent occurrences ofR^(o) (or R⁺, or any other variable similarly defined herein) that arebound to the same atom and are taken together with that atom to form aring, for example, N(R^(o))₂, where both occurrences of R^(o) are takentogether with the nitrogen atom to form a piperidin-1-yl,piperazin-1-yl, or morpholin-4-yl group; and b) two independentoccurrences of R^(o) (or R⁺, or any other variable similarly definedherein) that are bound to different atoms and are taken together withboth of those atoms to form a ring, for example where a phenyl group issubstituted with two occurrences of OR^(o)

these two occurrences of R^(o) are taken together with the oxygen atomsto which they are bound to form a fused 6-membered oxygen containingring

It will be appreciated that a variety of other rings can be formed whentwo independent occurrences of R^(o) (or R⁺, or any other variablesimilarly defined herein) are taken together with the atom(s) to whicheach variable is bound and that the examples detailed above are notintended to be limiting.

Unless otherwise stated, structures depicted herein are also meant toinclude all isomeric (e.g., enantiomeric, diastereomeric, and geometric(or conformational)) forms of the structure; for example, the R and Sconfigurations for each asymmetric center, (Z) and (E) double bondisomers, and (Z) and (E) conformational isomers. Therefore, singlestereochemical isomers as well as enantiomeric, diastereomeric, andgeometric (or conformational) mixtures of the present compounds arewithin the scope of the invention. Unless otherwise stated, alltautomeric forms of the compounds of the invention are within the scopeof the invention. Additionally, unless otherwise stated, structuresdepicted herein are also meant to include compounds that differ only inthe presence of one or more isotopically enriched atoms. For example,compounds having the present structures except for the replacement ofhydrogen by deuterium or tritium, or the replacement of a carbon by a¹³C- or ¹⁴C-enriched carbon are within the scope of this invention. Suchcompounds are useful, for example, as analytical tools or probes inbiological assays.

As used herein, the term “detectable moiety” is used interchangeablywith the term “label” and relates to any moiety capable of beingdetected, e.g., primary labels and secondary labels. Primary labels,such as radioisotopes (e.g., ³²P, ³³P, ³⁵S, or ¹⁴C), mass-tags, andfluorescent labels are signal generating reporter groups which can bedetected without further modifications.

The term “secondary label” as used herein refers to moieties such asbiotin and various protein antigens that require the presence of asecond intermediate for production of a detectable signal. For biotin,the secondary intermediate may include streptavidin-enzyme conjugates.For antigen labels, secondary intermediates may include antibody-enzymeconjugates. Some fluorescent groups act as secondary labels because theytransfer energy to another group in the process of nonradiativefluorescent resonance energy transfer (FRET), and the second groupproduces the detected signal.

The terms “fluorescent label”, “fluorescent dye”, and “fluorophore” asused herein refer to moieties that absorb light energy at a definedexcitation wavelength and emit light energy at a different wavelength.Examples of fluorescent labels include, but are not limited to: AlexaFluor dyes (Alexa Fluor 350, Alexa Fluor 488, Alexa Fluor 532, AlexaFluor 546, Alexa Fluor 568, Alexa Fluor 594, Alexa Fluor 633, AlexaFluor 660 and Alexa Fluor 680), AMCA, AMCA-S, BODIPY dyes (BODIPY FL,BODIPY R6G, BODIPY TMR, BODIPY TR, BODIPY 530/550, BODIPY 558/568,BODIPY 564/570, BODIPY 576/589, BODIPY 581/591, BODIPY 630/650, BODIPY650/665), Carboxyrhodamine 6G, carboxy-X-rhodamine (ROX), Cascade Blue,Cascade Yellow, Coumarin 343, Cyanine dyes (Cy3, Cy5, Cy3.5, Cy5.5),Dansyl, Dapoxyl, Dialkylaminocoumarin,4′,5′-Dichloro-2′,7′-dimethoxy-fluorescein, DM-NERF, Eosin, Erythrosin,Fluorescein, FAM, Hydroxycoumarin, IRDyes (IRD40, IRD 700, IRD 800),JOE, Lissamine rhodamine B, Marina Blue, Methoxycoumarin,Naphthofluorescein, Oregon Green 488, Oregon Green 500, Oregon Green514, Pacific Blue, PyMPO, Pyrene, Rhodamine B, Rhodamine 6G, RhodamineGreen, Rhodamine Red, Rhodol Green,2′,4′,5′,7′-Tetra-bromosulfone-fluorescein, Tetramethyl-rhodamine (TMR),Carboxytetramethylrhodamine (TAMRA), Texas Red, Texas Red-X.

The term “mass-tag” as used herein refers to any moiety that is capableof being uniquely detected by virtue of its mass using mass spectrometry(MS) detection techniques. Examples of mass-tags include electrophorerelease tags such asN-[3-[4′-[(p-Methoxytetrafluorobenzyl)oxy]phenyl]-3-methylglyceronyl]isonipecoticAcid, 4′-[2,3,5,6-Tetrafluoro-4-(pentafluorophenoxyl)]methylacetophenone, and their derivatives. The synthesis and utility of thesemass-tags is described in U.S. Pat. Nos. 4,650,750, 4,709,016,5,360,8191, 5,516,931, 5,602,273, 5,604,104, 5,610,020, and 5,650,270.Other examples of mass-tags include, but are not limited to,nucleotides, dideoxynucleotides, oligonucleotides of varying length andbase composition, oligopeptides, oligosaccharides, and other syntheticpolymers of varying length and monomer composition. A large variety oforganic molecules, both neutral and charged (biomolecules or syntheticcompounds) of an appropriate mass range (100-2000 Daltons) may also beused as mass-tags.

The term “metal substrate”, as used herein refers to any metallicmaterial which may be modified to incorporate hydroxyl groups to which afunctionalized end-group of a polymeric or small molecule organic groupcan be attached.

3. Description of Exemplary Embodiments

As described generally above, the present invention provides a methodfor covalently modifying a metal substrate, comprising the steps ofintroducing hydroxyl groups onto the metal substrate to produce ahydrophilic metal surface and covalently bonding a polymer or smallmolecule organic moiety onto the hydrophilic metal surface. As usedherein, the phrase “hydrophilic metal surface” refers to a metalsubstrate onto which a plurality of hydroxyl groups has beenincorporated. One of ordinary skill in the art would recognize thatvarious metallic substrates are amenable to methods of the presentinvention. In certain embodiments, the metal substrate is any suchsubstrate that comprises iron. In other embodiments, the metal substratecomprises a stainless steel, a cobalt alloy, or a titanium alloy. Instill other embodiments, the metal substrate comprises iron, ironalloys, steel, stainless steel, austenitic stainless steel, Type 316stainless steel, ferritic stainless steel, martensitic stainless steel,duplex stainless steel, cobalt, cobalt alloys, cobalt-chromium alloys,stellite alloys, Vitallium®, titanium, titanium alloys, nickel-titaniumalloys, nitinol, or super-alloys.

Hydrophilic metal surfaces can be prepared with the use of oxygen and/orwater plasmas. (Kim et. al. Surface and Coatings Technology, 2003, 171,312-316). It has been shown that hydroxyl groups, in the form ofFe(OH)₂, are the source of this hydrophilicity on the metal surface.(Suzuki et. al. Surface and Coatings Technology 2005, 200, 284-287).This strategy extends to a number of iron-based metals and alloys suchas iron, iron alloys, steel, stainless steel, austenitic stainlesssteel, Type 316 stainless steel, ferritic stainless steel, martensiticstainless steel, and duplex stainless steel. Other suitable metalsubstrates include cobalt, cobalt alloys, cobalt-chromium alloys,stellite alloys, Vitallium®, titanium, titanium alloys, nickel-titaniumalloys, nitinol, and super-alloys. The geometry of the metal substrateincludes, but is not limited to, flat surfaces, curved surfaces,cylinders, spheres, wire mesh, and tubing.

Using chemical functionality on the surface of plasma-treated metals, itwould be advantageous to perform additional chemical modification of thesubstrate through dehydration or condensation reactions. Such reactionsproceed on the hydrophilic metal surface without the need for additionalreagents or catalysts. Chemical functionalities that undergo dehydrationreactions with the plasma-modified metal substrates include, but are notlimited to, phosphonic acids, silyl-alcohols and carboxylic acids.(Raman, A.; Gawalt, E. S. Langmuir, 2007, 23, 2284-2288. Raman, A. et.al. Langmuir, 2006, 22, 6469-6472. Gao, W. et al. Langmuir, 1996, 12,6429-6435.) In addition, phosphonic halides, acyl halides, andsilyl-halides can undergo condensation reactions with hydroxylfunctionalized metal surfaces to afford the desired modified metallicmaterial.

In certain embodiments, the dehydration reaction is carried out by firstincubating the hydrophilic metal surface with the suitable functionalmolecule in an aqueous or organic solution. Without wishing to be boundby any particular theory, it is believed that during incubation,hydrogen bonding promotes the interaction of the functional moleculewith the modified metal surface. This hydrogen-bonded intermediate isthen converted to a covalent bond by subsequent dehydration. In certainembodiments, the dehydration step is performed at reduced pressureand/or elevated temperature. In other embodiments, the condensationreaction of acid-halide or silyl halide functional molecules andhydroxyl-functionalized metal substrates is performed using anhydrousconditions in dry organic solvents, leading directly to the desiredcovalently modified metal surface. One of ordinary still in the art willappreciate that the covalent bond forming reactions contemplated by thepresent invention are not limited to dehydration and condensationreactions and include, for example, addition reactions.

The introduction of hydroxyl groups onto a metal surface is well knownto one of ordinary skill in the art. One of ordinary skill wouldrecognize that there are multiple methods for accomplishing thefunctionalization of a metal substrate. One such method is the oxidationof iron atoms found in metal substrates. Such oxidation is well known inthe art and includes cold plasma methods as described by, e.g., Suzuki,et al, Surface & Coatings Technology, (2005) 284-287. In certainembodiments, the metal substrate is oxidized with water vapor plasma.

As described generally above, the functionalized metal surface iscovalently bonded to a polymer or a small molecule organic moiety. Oneof ordinary skill in the art would appreciate that hydroxyl groups arecovalently bonded to a variety of other functional groups (e.g., withcarboxylic acids to form esters thereof) by condensation or dehydrationreaction. All such functional groups capable of covalently bonding tothe hydroxyl groups incorporated onto the metal surface arecontemplated. In certain embodiments, the polymer or small moleculeorganic moiety comprises one or more functional groups capable ofcovalently bonding to one or more hydroxyl groups incorporated onto themetal surface. Exemplary functional groups include, but are not limitedto, phosphonic acids, silyl-alcohols, carboxylic acids, phosphonichalides, acyl halides, and silyl-halides.

Polymeric groups for use in the present invention comprise one or morefunctional groups capable of covalently bonding with one or morehydroxyl groups incorporated onto the metal surface. It will beappreciated that many such polymeric groups are amenable to thisreaction. These polymeric groups include natural or synthetic polymersand copolymers. Exemplary polymers include mono-functionalized PEG's,poly(amino acids), heterobifunctional PEG's, branched PEG's,heterofunctionalized branched PEG's, PEG-b-PAA-b-PAA block copolymer,PEG-b-PAA-b-PEG block copolymers, PEG-b-polyester-b-PEG blockcopolymers, PEG-b-PAA block copolymers, [where PAA refers to poly(aminoacid)], dextran, heparin, fibronectin, chitosan, amylose, amylopectin,glycogen, xanthan, gellan, pullulun, cellulose, and cellulose acetate.

In certain embodiments, the present invention provides a method forpreparing a covalently modified metal surface, comprising the steps of:

(a) modifying a metal substrate to incorporate thereon a plurality ofhydroxyl groups;(b) providing a compound of formula I:

R¹—W  I

wherein:

-   R¹ is a natural or synthetic polymer or copolymer group or a small    molecule organic group;-   W is —C(═O)OH, —C(═O)X, —P(═O)(OH)₂, —P(═O)(X)₂, —P(═O)(R^(a))OH,    —P(═O)(R^(a))X, —O—S(═O)₂OH, —S(═O)₂OH, —Si(R^(a))₂OH,    —Si(OR^(a))₂OH, —Si(R^(a))₂X, —Si(R^(a))(OH)₂, —Si(R^(a))X₂,    —Si(OR^(a))₂X, C(═O)H, —N═C═S, —N═C═O, phenol, thiophenol, or an    epoxide;-   each X is independently Cl, Br, or I; and-   each R^(a) is hydrogen, an alkyl group, or an aryl group;-   and    (c) coupling the compound of formula I to one or more of the    hydroxyl groups on the metal surface.

As described generally above, the coupling step (c) can be performed inthe absence of reagents or catalysts by dehydration or condensation.However, it is also contemplated that the coupling step (c) can beperformed in the presence of such reagents or catalysts. For example,coupling step (c) may be performed in the presence of a suitable base.Suitable bases include any of those known to one of ordinary skill inthe art for such coupling reactions. Exemplary bases include, but arenot limited to, triethylamine, diisopropylamine, diisopropylethylamine,dimethylaminopyridine, and the like.

One of ordinary skill in the art will appreciate that when W is —C(═O)X,—P(═O)(X)₂, —P(═O)(R^(a))X, —Si(R^(a))₂X, or —Si(OR^(a))₂X, then thecoupling at step (c) can occur by a condensation reaction. See FIGS. 2,4, 6, 8, 10, and 12 which depict representative methods of the presentinvention whereby coupling step (c) occurs by condensation reaction.

Similarly, when W is —C(═O)OH, —P(═O)(OH)₂, —P(═O)(R^(a))OH,—Si(R^(a))₂OH, or —Si(OR^(a))₂OH, the coupling at step (c) can occur bya dehydration reaction. See FIGS. 1, 3, 5, 7, 9, and 11 which depictrepresentative methods of the present invention whereby coupling step(c) occurs by dehydration reaction.

In certain embodiments, the metal substrate comprises iron, iron alloys,steel, stainless steel, austenitic stainless steel, Type 316 stainlesssteel, ferritic stainless steel, martensitic stainless steel, duplexstainless steel, cobalt, cobalt alloys, cobalt-chromium alloys, stellitealloys, Vitallium®, titanium, titanium alloys, nickel-titanium alloys,nitinol, or super-alloys.

In other embodiments, R¹ is a synthetic polymer such as linearhomopolymers, branched homopolymers, block copolymers, branched blockcopolymers, star polymers, star copolymers, graft copolymers,hyperbranched copolymers, and dendrimers. In still other embodiments, R¹is a natural polymer such as oligopeptides, proteins, polynucleic acids(e.g. DNA and RNA), oligosaccharides, and polysaccharides. According toanother aspect of the present invention, R¹ is poly(ethylene glycol)(PEG), a heterobifunctional PEG, a branched PEG, heterofunctionalizedbranched PEG's, PEG-b-PAA-b-PAA block copolymer, PEG-b-PAA-b-PEG blockcopolymers, PEG-b-polyester-b-PEG block copolymers, PEG-b-PAA blockcopolymers, [where PAA refers to poly(amino acid)], dextran, heparin,fibronectin, chitosan, amylose, amylopectin, glycogen, xanthan, gellan,pullulun, cellulose, and cellulose acetate.

In certain embodiments, R¹ is a small molecule organic group. In otherembodiments, R¹ is selected from monosaccharides (e.g., glucose,galactose, fructose) and disaccharides (e.g., sucrose, lactose,maltose), phosphorylcholines, phosoplipids, cyclodextrans, and smallmolecule drugs.

In other embodiments, the present invention provides a method forpreparing a covalently modified metal surface, comprising the steps of:

(a) providing a metal surface having a plurality of hydroxyl groups;(b) providing a compound of formula I:

R¹—W  I

wherein:

-   R¹ is a natural or synthetic polymer or copolymer group or a small    molecule organic group;-   W is —C(═O)OH, —C(═O)X, —P(═O)(OH)₂, —P(═O)(X)₂, —P(═O)(R^(a))OH,    —P(═O)(R^(a))X, —O—S(═O)₂OH, —S(═O)₂OH, —Si(R^(a))₂OH,    —Si(OR^(a))₂OH, —Si(R^(a))₂X, —Si(R^(a))(OH)₂, —Si(R^(a))X₂,    —Si(OR^(a))₂X, C(═O)H, —N═C═S, —N═C═O, phenol, thiophenol, or an    epoxide;-   each X is independently Cl, Br, or I; and-   each R^(a) is hydrogen, an alkyl group, or an aryl group;-   and    (c) coupling the compound of formula I to one or more of the    hydroxyl groups on the metal surface.

Polymer Groups

As defined generally above, R¹ is a natural or synthetic polymer orcopolymer group or a small molecule organic group. In certainembodiments, R¹ is a poly(alkylene oxide) group or a branchedpoly(alkylene oxide). In other embodiments, R¹ is a poly(ethyleneglycol) group (“PEG”). PEG's are well known to one of ordinary skill inthe art and include those described in detail in International PatentApplication publication number WO2006/047419, U.S. Provisional PatentApplication Ser. No. 60/795,412, filed Apr. 27, 2006, and U.S.Provisional Patent Application Ser. No. 60/795,374, filed Apr. 27, 2006,the entirety of each of which is hereby incorporated herein byreference. According to another aspect of the present invention, R¹ is agroup of formula II:

or a salt thereof, wherein:

-   y is 0-2500;-   R² is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X′)₂, a small molecule drug, a 9-30 membered crown    ether, a mono-protected amine, a di-protected amine, a protected    aldehyde, a protected hydroxyl, a protected carboxylic acid, a    protected thiol, or an optionally substituted group selected from    aliphatic, a 3-8 membered saturated, partially unsaturated, or aryl    ring having 0-4 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, an 8-10 membered saturated, partially    unsaturated, or aryl bicyclic ring having 0-5 heteroatoms    independently selected from nitrogen, oxygen, or sulfur, or a    detectable moiety;-   each X′ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur; and-   L² is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L² are independently replaced by -Cy-, —O—, —NR—, —S—, or    —C(O)—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur.

As defined generally above, the y group of formula II is 0-2500. Incertain embodiments, the y group of formula II is 0. In certainembodiments, the present invention provides compounds of formula II, asdescribed above, wherein y is about 225. In other embodiments, y isabout 10 to about 40. In other embodiments, y is about 40 to about 60.In still other embodiments, y is about 90 to about 150. In still otherembodiments, y is about 200 to about 250. In other embodiments, y isabout 300 to about 375. In other embodiments, y is about 400 to about500. In still other embodiments, y is about 650 to about 750. In stillother embodiments, y is about 1 to about 10.

In certain embodiments, R² is optionally substituted aliphatic. In otherembodiments, R² is an unsubstituted aliphatic. In some embodiments, saidR² moiety is an optionally substituted alkyl group. In otherembodiments, said R² moiety is an optionally substituted alkynyl oralkenyl group. Such groups include methyl, t-butyl, 5-norbornene-2-yl,octane-5-yl, —C≡CH, —CH₂C≡CH, —CH₂CH₂C≡CH, and —CH₂CH₂CH₂C≡CH. When saidR² moiety is a substituted aliphatic group, suitable substituents on R²include any of CN, N₃, NO₂, —CO₂H, —SH, —NH₂, —C(O)H, —NHC(O)R^(o),—NHC(S)R^(o), —NHC(O)NR^(o) ₂, —NHC(S)NR^(o) ₂, —NHC(O)OR^(o),—NHNHC(O)R^(o), —NHNHC(O)NR^(o) ₂, —NHNHC(O)OR^(o), —C(O)R^(o),—C(S)R^(o), —C(O)OR^(o), —C(O)SR^(o), —C(O)OSiR^(o) ₃, —OC(O)R^(o),SC(S)SR^(o), —SC(O)R^(o), —C(O)N(R^(o))₂, —C(S)N(R^(o))₂, —C(S)SR^(o),—SC(S)SR^(o), —OC(O)N(R^(o))₂, —C(O)NHN(R^(o))₂, —C(O)N(OR^(o))R^(o),—C(O)C(O)R^(o), —C(O)CH₂C(O)R^(o), —C(NOR^(o))R^(o), —SSR^(o),—S(O)₂R^(o), —S(O)₂OR^(o), —OS(O)₂R^(o), —S(O)₂N(R^(o))₂, —S(O)R^(o),—N(R^(o))S(O)₂N(R^(o))₂, —N(R^(o))S(O)₂R^(o), —N(OR^(o))R^(o),—C(NH)N(R^(o))₂, —P(O)₂R^(o), —P(O)(R^(o))₂, —OP(O)(R^(o))₂, or—OP(O)(OR^(o))₂, wherein each R^(o) is as defined herein.

In other embodiments, R² is an aliphatic group optionally substitutedwith any of Cl, Br, I, F, —NH2, —OH, —SH, —CO₂H, —C(O)H, —C(O)(C₁₋₆aliphatic), —NHC(O)(C₁₋₆ aliphatic), —NHC(O)NH₂, —NHC(O)NH(C₁₋₆aliphatic), —NHC(S)NH—, —NHC(S)N(C₁₋₆ aliphatic)₂, —NHC(O)O(C₁₋₆aliphatic), —NHNH₂, —NHNHC(O)(C₁₋₆ aliphatic), —NHNHC(O)NH₂,—NHNHC(O)NH(C₁₋₆ aliphatic), —NHNHC(O)O(C₁₋₆ aliphatic), —C(O)NH₂,—C(O)NH(C₁₋₆ aliphatic)₂, —C(O)NHNH₂, —C(S)N(C₁₋₆ aliphatic)₂,—OC(O)NH(C₁₋₆ aliphatic), —C(O)C(O)(C₁₋₆ aliphatic), —C(O)CH₂C(O)(C₁₋₆aliphatic), —S(O)₂(C₁₋₆ aliphatic), —S(O)₂O(C₁₋₆ aliphatic),—OS(O)₂(C₁₋₆ aliphatic), —S(O)₂NH(C₁₋₆ aliphatic), —S(O)(C₁₋₆aliphatic), —NHS(O)₂NH(C₁₋₆ aliphatic), —NHS(O)₂(C₁₋₆ aliphatic),—P(O)₂(C₁₋₆ aliphatic), —P(O)(C₁₋₆ aliphatic)₂, —OP(O)(C₁₋₆ aliphatic)₂,or —OP(O)(OC₁₋₆ aliphatic)₂.

In certain embodiments, the R² group of formula II is a group suitablefor Click chemistry. Click reactions tend to involve high-energy(“spring-loaded”) reagents with well-defined reaction coordinates, thatgive rise to selective bond-forming events of wide scope. Examplesinclude nucleophilic trapping of strained-ring electrophiles (epoxide,aziridines, aziridinium ions, episulfonium ions), certain carbonylreactivity (e.g., the reaction between aldehydes and hydrazines orhydroxylamines), and several cycloaddition reactions. The azide-alkyne1,3-dipolar cycloaddition is one such reaction. Click chemistry is knownin the art and one of ordinary skill in the art would recognize thatcertain R² moieties of the present invention are suitable for Clickchemistry.

According to one embodiment, the R² group of formula II is anazide-containing group. According to another embodiment, the R² group offormula II is an alkyne-containing group. In certain embodiments, the R²group of formula II has a terminal alkyne moiety. According to anotherembodiment, the R² group of formula II is an aldehyde-containing group.In certain embodiments, the R² group of formula II has a terminalhydrazine moiety. In other embodiments, the R² group of formula II has aterminal oxyamine moiety. In still other embodiments, the R² group offormula II is a epoxide-containing group. In certain other embodiments,the R² group of formula II has a terminal maleimide moiety.

In other embodiments, R² is an optionally substituted 3-8 memberedsaturated, partially unsaturated, or aryl ring having 0-4 heteroatomsindependently selected from nitrogen, oxygen, or sulfur, an 8-10membered saturated, partially unsaturated, or aryl bicyclic ring having0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur.In certain embodiments, R² is an optionally substituted 5-7 memberedsaturated or partially unsaturated ring having 0-4 heteroatomsindependently selected from nitrogen, oxygen, or sulfur. In otherembodiments, R² is an optionally substituted phenyl ring or a 5-6membered heteroaryl ring having 1-4 heteroatoms independently selectedfrom nitrogen, oxygen, or sulfur.

In certain embodiments, the R² group of formula II is an optionallysubstituted aryl group. Examples include optionally substituted phenyl,optionally substituted pyridyl, optionally substituted naphthyl,optionally substituted pyrenyl, optionally substituted triazole,optionally substituted imidazole, optionally substituted phthalimide,optionally substituted tetrazole, optionally substituted furan, andoptionally substituted pyran. When said R² moiety is a substituted arylgroup, suitable substituents on R² include any of R^(o), CN, N₃, NO₂,—CH₃, —CH₂N₃, t-butyl, 5-norbornene-2-yl, octane-5-yl, —CH═CH₂,—CH₂C≡CH, —CH₂CH₂C≡CH, —CH₂CH₂CH₂C≡CH, Cl, Br, I, F, —NH₂, —OH, —SH,—CO₂H, —C(O)H, —CH₂NH₂, —CH₂OH, —CH₂SH, —CH₂CO₂H, —CH₂C(O)H, —C(O)(C₁₋₆aliphatic), —NHC(O)(C₁₋₆ aliphatic), —NHC(O)NH—, —NHC(O)NH(C₁₋₆aliphatic), —NHC(S)NH₂, —NHC(S)N(C₁₋₆ aliphatic)₂, —NHC(O)O(C₁₋₆aliphatic), —NHNH₂, —NHNHC(O)(C₁₋₆ aliphatic), —NHNHC(O)NH₂,—NHNHC(O)NH(C₁₋₆ aliphatic), —NHNHC(O)O(C₁₋₆ aliphatic), —C(O)NH₂,—C(O)NH(C₁₋₆ aliphatic)₂, —C(O)NHNH₂, —C(S)N(C₁₋₆ aliphatic)₂,—OC(O)NH(C₁₋₆ aliphatic), —C(O)C(O)(C₁₋₆ aliphatic), —C(O)CH₂C(O)(C₁₋₆aliphatic), —S(O)₂(C₁₋₆ aliphatic), —S(O)₂O(C₁₋₆ aliphatic),—OS(O)₂(C₁₋₆ aliphatic), —S(O)₂NH(C₁₋₆ aliphatic), —S(O)(C₁₋₆aliphatic), —NHS(O)₂NH(C₁₋₆ aliphatic), —NHS(O)₂(C₁₋₆ aliphatic),—P(O)₂(C₁₋₆ aliphatic), —P(O)(C₁₋₆ aliphatic)₂, —OP(O)(C₁₋₆ aliphatic)₂,or —OP(O)(OC₁₋₆ aliphatic)₂.

Suitable substitutents on R² further includebis-(4-ethynyl-benzyl)-amino, dipropargylamino, di-hex-5-ynyl-amino,di-pent-4-ynyl-amino, di-but-3-ynyl-amino, propargyloxy, hex-5-ynyloxy,pent-4-ynyloxy, di-but-3-ynyloxy, 2-hex-5-ynyloxy-ethyldisulfanyl,2-pent-4-ynyloxy-ethyldisulfanyl, 2-but-3-ynyloxy-ethyldisulfanyl,2-propargyloxy-ethyldisulfanyl, bis-benzyloxy-methyl,[1,3]dioxolan-2-yl, and [1,3]dioxan-2-yl.

In other embodiments, R² is hydrogen.

According to one embodiment, R² is methyl.

In certain embodiments, R² is N₃.

In other embodiments, R² is an epoxide ring.

In certain embodiments, the R² group of formula II is a crown ether.Examples of such crown ethers include 12-crown-4, 15-crown-5, and18-crown-6.

In still other embodiments, R² is a detectable moiety. Detectablemoieties are known in the art and include those described herein.According to one aspect of the invention, the R² group of formula II isa fluorescent moiety. Such fluorescent moieties are well known in theart and include coumarins, quinolones, benzoisoquinolones, hostasol, andRhodamine dyes, to name but a few. Exemplary fluorescent moieties of R²include anthracen-9-yl, pyren-4-yl, 9-H-carbazol-9-yl, the carboxylateof rhodamine B, and the carboxylate of coumarin 343. In certainembodiments, R² is a detectable moiety selected from:

In certain embodiments, R² is —P(O)(OR)₂, or —P(O)(halogen)₂. Accordingto one aspect, the present invention provides a compound of formula II,wherein R² is —P(O)(OH)₂. According to another aspect, the presentinvention provides a compound of formula II, wherein R² is —P(O)(Cl)₂.One of ordinary skill in the art would recognize that when R² is—P(O)(OR)₂, or —P(O)(halogen)₂, the R² group is also capable of forminga covalent bond with the hydrophilic metal surface thus forming a“looped” attachment.

As defined generally above, the L¹ group of formula II is a valence bondor a bivalent, saturated or unsaturated, straight or branched C₁₋₁₂alkylene chain, wherein 0-6 methylene units of L¹ are independentlyreplaced by -Cy-, —O—, —NR—, —S—, —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—,—NRSO₂—, —SO₂NR—, —NRC(O)—, —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, whereineach -Cy- is independently an optionally substituted 3-8 memberedbivalent, saturated, partially unsaturated, or aryl ring having 0-4heteroatoms independently selected from nitrogen, oxygen, or sulfur, oran optionally substituted 8-10 membered bivalent saturated, partiallyunsaturated, or aryl bicyclic ring having 0-5 heteroatoms independentlyselected from nitrogen, oxygen, or sulfur.

In certain embodiments, L¹ is a valence bond. In other embodiments, L¹is a bivalent, saturated C₁₋₁₂ alkylene chain, wherein 0-6 methyleneunits of L¹ are independently replaced by -Cy-, —O—, —NH—, —S—, —OC(O)—,—C(O)O—, —C(O)—, —C(O)NH—, or —NHC(O)—, wherein each -Cy- isindependently an optionally substituted 3-8 membered bivalent,saturated, partially unsaturated, or aryl ring having 0-4 heteroatomsindependently selected from nitrogen, oxygen, or sulfur, or anoptionally substituted 8-10 membered bivalent saturated, partiallyunsaturated, or aryl bicyclic ring having 0-5 heteroatoms independentlyselected from nitrogen, oxygen, or sulfur. In still other embodiments,L¹ is a bivalent, saturated C₁₋₆ alkylene chain, wherein 0-3 methyleneunits of L¹ are independently replaced by -Cy-, —O—, —NH—, —S—, —OC(O)—,—C(O)O—, —C(O)—, —C(O)NH—, or —NHC(O)—.

In certain embodiments, L¹ is -Cy- (i.e. a C₁ alkylene chain wherein themethylene unit is replaced by -Cy-), wherein -Cy- is an optionallysubstituted 3-8 membered bivalent, saturated, partially unsaturated, oraryl ring having 0-4 heteroatoms independently selected from nitrogen,oxygen, or sulfur. According to one aspect of the present invention,-Cy- is an optionally substituted bivalent aryl group. According toanother aspect of the present invention, -Cy- is an optionallysubstituted bivalent phenyl group. In other embodiments, -Cy- is anoptionally substituted 5-8 membered bivalent, saturated carbocyclicring. In still other embodiments, -Cy- is an optionally substituted 5-8membered bivalent, saturated heterocyclic ring having 1-2 heteroatomsindependently selected from nitrogen, oxygen, or sulfur. Exemplary -Cy-groups include bivalent rings selected from phenyl, pyridyl,pyrimidinyl, cyclohexyl, cyclopentyl, or cyclopropyl.

In certain embodiments, the L¹ group of formula II is —O—, —S—, —NH—, or—C(O)O—. In other embodiments, the L¹ group of formula II is -Cy-,—C(O)—, —C(O)NH—, —NHC(O)—, —NH—O—, or —O-Cy-CH₂NH—O—. In still otherembodiments, the L¹ group of formula II is any of —OCH₂—, —OCH₂C(O)—,—OCH₂CH₂C(O)—, —OCH₂CH₂O—, —OCH₂CH₂S—, —OCH₂CH₂C(O)O—, —OCH₂CH₂NH—,—OCH₂CH₂NHC(O)—, —OCH₂CH₂C(O)NH—, and —NHC(O)CH₂CH₂C(O)O—. According toanother aspect, the L¹ group of formula II is any of—OCH₂CH₂NHC(O)CH₂CH₂C(O)O—, —OCH₂CH₂NHC(O)CH₂OCH₂C(O)O—,—OCH₂CH₂NHC(O)CH₂OCH₂C(O)NH—, —CH₂C(O)NH—, —CH₂C(O)NHNH—, or—OCH₂CH₂NHNH—.

As defined generally above, the R² group of formula II is, inter alia, amono-protected amine, a di-protected amine, a protected aldehyde, aprotected hydroxyl, a protected carboxylic acid, or a protected thiol.Protected hydroxyl groups are well known in the art and include thosedescribed in detail in Protecting Groups in Organic Synthesis, T. W.Greene and P. G. M. Wuts, 3^(rd) edition, John Wiley & Sons, 1999, theentirety of which is incorporated herein by reference. Examples ofsuitably protected hydroxyl groups further include, but are not limitedto, esters, carbonates, sulfonates allyl ethers, ethers, silyl ethers,alkyl ethers, arylalkyl ethers, and alkoxyalkyl ethers. Examples ofsuitable esters include formates, acetates, proprionates, pentanoates,crotonates, and benzoates. Specific examples of suitable esters includeformate, benzoyl formate, chloroacetate, trifluoroacetate,methoxyacetate, triphenylmethoxyacetate, p-chlorophenoxyacetate,3-phenylpropionate, 4-oxopentanoate, 4,4-(ethylenedithio)pentanoate,pivaloate (trimethylacetate), crotonate, 4-methoxy-crotonate, benzoate,p-benzylbenzoate, 2,4,6-trimethylbenzoate. Examples of suitablecarbonates include 9-fluorenylmethyl, ethyl, 2,2,2-trichloroethyl,2-(trimethylsilyl)ethyl, 2-(phenylsulfonyl)ethyl, vinyl, allyl, andp-nitrobenzyl carbonate. Examples of suitable silyl ethers includetrimethylsilyl, triethylsilyl, t-butyldimethylsilyl,t-butyldiphenylsilyl, triisopropylsilyl ether, and other trialkylsilylethers. Examples of suitable alkyl ethers include methyl, benzyl,p-methoxybenzyl, 3,4-dimethoxybenzyl, trityl, t-butyl, and allyl ether,or derivatives thereof. Alkoxyalkyl ethers include acetals such asmethoxymethyl, methylthiomethyl, (2-methoxyethoxy)methyl,benzyloxymethyl, beta-(trimethylsilyl)ethoxymethyl, andtetrahydropyran-2-yl ether. Examples of suitable arylalkyl ethersinclude benzyl, p-methoxybenzyl (MPM), 3,4-dimethoxybenzyl,O-nitrobenzyl, p-nitrobenzyl, p-halobenzyl, 2,6-dichlorobenzyl,p-cyanobenzyl, 2- and 4-picolyl ethers.

Protected amines are well known in the art and include those describedin detail in Greene (1999). Suitable mono-protected amines furtherinclude, but are not limited to, aralkylamines, carbamates, allylamines, amides, and the like. Examples of suitable mono-protected aminomoieties include t-butyloxycarbonylamino (—NHBOC),ethyloxycarbonylamino, methyloxycarbonylamino,trichloroethyloxycarbonylamino, allyloxycarbonylamino (—NHAlloc),benzyloxocarbonyl amino (—NHCBZ), allylamino, benzylamino (—NHBn),fluorenylmethylcarbonyl (—NHFmoc), formamido, acetamido,chloroacetamido, dichloroacetamido, trichloroacetamido, phenylacetamido,trifluoroacetamido, benzamido, t-butyldiphenylsilyl, and the like.Suitable di-protected amines include amines that are substituted withtwo substituents independently selected from those described above asmono-protected amines, and further include cyclic imides, such asphthalimide, maleimide, succinimide, and the like. Suitable di-protectedamines also include pyrroles and the like,2,2,5,5-tetramethyl-[1,2,5]azadisilolidine and the like, and azide.

Protected aldehydes are well known in the art and include thosedescribed in detail in Greene (1999). Suitable protected aldehydesfurther include, but are not limited to, acyclic acetals, cyclicacetals, hydrazones, imines, and the like. Examples of such groupsinclude dimethyl acetal, diethyl acetal, diisopropyl acetal, dibenzylacetal, bis(2-nitrobenzyl)acetal, 1,3-dioxanes, 1,3-dioxolanes,semicarbazones, and derivatives thereof.

Protected carboxylic acids are well known in the art and include thosedescribed in detail in Greene (1999). Suitable protected carboxylicacids further include, but are not limited to, optionally substitutedC₁₋₆ aliphatic esters, optionally substituted aryl esters, silyl esters,activated esters, amides, hydrazides, and the like. Examples of suchester groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl,benzyl, and phenyl ester, wherein each group is optionally substituted.Additional suitable protected carboxylic acids include oxazolines andortho esters.

Protected thiols are well known in the art and include those describedin detail in Greene (1999). Suitable protected thiols further include,but are not limited to, disulfides, thioethers, silyl thioethers,thioesters, thiocarbonates, and thiocarbamates, and the like. Examplesof such groups include, but are not limited to, alkyl thioethers, benzyland substituted benzyl thioethers, triphenylmethyl thioethers, andtrichloroethoxycarbonyl thioester, to name but a few.

As defined generally above, the L² group of formula II is L² is avalence bond or a bivalent, saturated or unsaturated, straight orbranched C₁₋₁₂ alkylene chain, wherein 0-6 methylene units of L² areindependently replaced by -Cy-, —O—, —NR—, —S—, or —C(O)—, wherein each-Cy- is independently an optionally substituted 3-8 membered bivalent,saturated, partially unsaturated, or aryl ring having 0-4 heteroatomsindependently selected from nitrogen, oxygen, or sulfur, or anoptionally substituted 8-10 membered bivalent saturated, partiallyunsaturated, or aryl bicyclic ring having 0-5 heteroatoms independentlyselected from nitrogen, oxygen, or sulfur.

In certain embodiments, L² is a valence bond. In other embodiments, L²is a bivalent, saturated C₁₋₁₂ alkylene chain, wherein 0-6 methyleneunits of L² are independently replaced by -Cy-, or —O—, —NH—, whereineach -Cy- is independently an optionally substituted 5-8 memberedbivalent, saturated, partially unsaturated, or aryl ring having 0-4heteroatoms independently selected from nitrogen, oxygen, or sulfur, oran optionally substituted 8-10 membered bivalent saturated, partiallyunsaturated, or aryl bicyclic ring having 0-5 heteroatoms independentlyselected from nitrogen, oxygen, or sulfur. In still other embodiments,L² is a bivalent, saturated C₁₋₆ alkylene chain, wherein 0-2 methyleneunits of L² are independently replaced by -Cy-.

In certain embodiments, L² is -Cy- (i.e., a C₁ alkylene chain whereinthe methylene unit is replaced by -Cy-), wherein -Cy- is an optionallysubstituted 3-8 membered bivalent, saturated, partially unsaturated, oraryl ring having 0-4 heteroatoms independently selected from nitrogen,oxygen, or sulfur. According to one aspect of the present invention,-Cy- is an optionally substituted bivalent aryl group. According toanother aspect of the present invention, -Cy- is an optionallysubstituted bivalent phenyl group. In other embodiments, -Cy- is anoptionally substituted 5-8 membered bivalent, saturated carbocyclicring. In still other embodiments, -Cy- is an optionally substituted 5-8membered bivalent, saturated heterocyclic ring having 1-2 heteroatomsindependently selected from nitrogen, oxygen, or sulfur. Exemplary -Cy-groups include bivalent rings selected from phenyl, pyridyl,pyrimidinyl, cyclohexyl, cyclopentyl, or cyclopropyl.

In certain embodiments, the L² group of formula II is —O—, —S—, —NH—, or—C(O)—. In still other embodiments, the L² group of formula II is any of—OCH₂—, —OCH₂C(O)—, —OCH₂CH₂C(O)—, —OCH₂CH₂O—, or —OCH₂CH₂S—. In otherembodiments, the L² group of formula II is —OC(O)CH₂CH₂CH₂CH₂—,—OCH₂CH₂—, —NHC(O)CH₂CH₂—, —NHC(O)CH₂CH₂CH₂—, —OC(O)CH₂CH₂CH₂—, —O-Cy-,—O-Cy-CH₂—, —O-Cy-NH—, —O-Cy-S—, —O-Cy-C(O)—, or —O-Cy-C(O)O-Cy-.

In certain embodiments, the present invention provides a method forpreparing a covalently modified metal surface, comprising the steps of:

(a) modifying a metal substrate to incorporate thereon a plurality ofhydroxyl groups;(b) providing a compound of formula II-a:

or a salt thereof, wherein:

-   W is —C(═O)OH, —C(═O)X, —P(═O)(OH)₂, —P(═O)(X)₂, —P(═O)(R^(a))OH,    —P(═O)(R^(a))X, —O—S(═O)₂OH, —S(═O)₂OH, —Si(R^(a))₂OH,    —Si(OR^(a))₂OH, —Si(R^(a))₂X, —Si(R^(a))(OH)₂, —Si(R^(a))X₂,    —Si(OR^(a))₂X, C(═O)H, —N═C═S, —N═C═O, phenol, thiophenol, or an    epoxide;-   each X is independently Cl, Br, or I; and-   each R^(a) is hydrogen, an alkyl group, or an aryl group;-   y is 0-2500;-   R² is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X′)₂, a 9-30 membered crown ether, a    mono-protected amine, a di-protected amine, a protected aldehyde, a    protected hydroxyl, a protected carboxylic acid, a protected thiol,    or an optionally substituted group selected from aliphatic, a 3-8    membered saturated, partially unsaturated, or aryl ring having 0-4    heteroatoms independently selected from nitrogen, oxygen, or sulfur,    an 8-10 membered saturated, partially unsaturated, or aryl bicyclic    ring having 0-5 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, or a detectable moiety;-   each X′ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur; and-   L² is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L² are independently replaced by -Cy-, —O—, —NR—, —S—, or    —C(O)—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur.-   and    (c) coupling the compound of formula II-a to one or more of the    hydroxyl groups on the metal surface.

Each of the R², L¹, y, and L² groups of formula II-a are as described inclasses and subclasses for compounds of formula II, both singly and incombination.

In other embodiments, the present invention provides a compound offormula II-a′:

or a salt thereof, wherein:

-   W is —Si(R^(a))₂OH, —Si(OR^(a))₂OH, —Si(R^(a))₂X, —Si(R^(a))(OH)₂,    —Si(R^(a))X₂, or —Si(OR^(a))₂X;-   each X is independently Cl, Br, or I; and-   each R^(a) is hydrogen, an alkyl group, or an aryl group;-   y is 0-2500;-   R² is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X′)₂, a 9-30 membered crown ether, a    mono-protected amine, a di-protected amine, a protected aldehyde, a    protected hydroxyl, a protected carboxylic acid, a protected thiol,    or an optionally substituted group selected from aliphatic, a 3-8    membered saturated, partially unsaturated, or aryl ring having 0-4    heteroatoms independently selected from nitrogen, oxygen, or sulfur,    an 8-10 membered saturated, partially unsaturated, or aryl bicyclic    ring having 0-5 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, or a detectable moiety;-   each X′ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur; and-   L² is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L² are independently replaced by -Cy-, —O—, —NR—, —S—, or    —C(O)—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur.

Each of the R², L¹, y, and L² groups of formula II-a′ are as describedin classes and subclasses for compounds of formula II, both singly andin combination.

In other embodiments, the present invention provides a method forpreparing a covalently modified metal surface, comprising the steps of:

(a) modifying a metal substrate to incorporate thereon a plurality ofhydroxyl groups;(b) providing a compound of formula II-b:

or a salt thereof, wherein:

-   y is 10-2500;-   R² is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X′)₂, a 9-30 membered crown ether, a    mono-protected amine, a di-protected amine, a protected aldehyde, a    protected hydroxyl, a protected carboxylic acid, a protected thiol,    or an optionally substituted group selected from aliphatic, a 3-8    membered saturated, partially unsaturated, or aryl ring having 0-4    heteroatoms independently selected from nitrogen, oxygen, or sulfur,    an 8-10 membered saturated, partially unsaturated, or aryl bicyclic    ring having 0-5 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, or a detectable moiety;-   each X′ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur; and-   L² is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L² are independently replaced by -Cy-, —O—, —NR—, —S—, or    —C(O)—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur.-   and    (c) coupling the compound of formula II-b to one or more of the    hydroxyl groups on the metal surface by dehydration reaction.

Each of the R², L¹, y, and L² groups of formula II-b are as described inclasses and subclasses for compounds of formula II, both singly and incombination.

In other embodiments, the present invention provides a method forpreparing a covalently modified metal surface, comprising the steps of:

(a) modifying a metal substrate to incorporate thereon a plurality ofhydroxyl groups;(b) providing a compound of formula II-c:

or a salt thereof, wherein:

-   y is 10-2500;-   R² is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X′)₂, a 9-30 membered crown ether, a    mono-protected amine, a di-protected amine, a protected aldehyde, a    protected hydroxyl, a protected carboxylic acid, a protected thiol,    or an optionally substituted group selected from aliphatic, a 3-8    membered saturated, partially unsaturated, or aryl ring having 0-4    heteroatoms independently selected from nitrogen, oxygen, or sulfur,    an 8-10 membered saturated, partially unsaturated, or aryl bicyclic    ring having 0-5 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, or a detectable moiety;-   each X′ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur; and-   L² is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L² are independently replaced by -Cy-, —O—, —NR—, —S—, or    —C(O)—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur.-   and    (c) coupling the compound of formula II-c to one or more of the    hydroxyl groups on the metal surface by condensation reaction.

Each of the R², y, and L² groups of formula II-c are as described inclasses and subclasses for compounds of formula II, both singly and incombination.

In certain embodiments, the R¹ group of formula I is a group of formulaII-d:

or a salt thereof, wherein:

-   y is 0-2500;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur; and-   L² is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L² are independently replaced by -Cy-, —O—, —NR—, —S—, or    —C(O)—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur.

Each of the L¹, y, and L² groups of formula II-d are as described inclasses and subclasses for compounds of formula II, both singly and incombination.

In certain embodiments, the present invention provides a method forpreparing a covalently modified metal surface, comprising the steps of:

(a) modifying a metal substrate to incorporate thereon a plurality ofhydroxyl groups;(b) providing a compound of formula II-e:

or a salt thereof, wherein:

-   W is —C(═O)OH, —C(═O)X, —P(═O)(OH)₂, —P(═O)(X)₂, —P(═O)(R^(a))OH,    —P(═O)(R^(a))X, —O—S(═O)₂OH, —S(═O)₂OH, —Si(R^(a))₂OH,    —Si(OR^(a))₂OH, —Si(R^(a))₂X, —Si(R^(a))(OH)₂, —Si(R^(a))X₂,    —Si(OR^(a))₂X, C(═O)H, —N═C═S, —N═C═O, phenol, thiophenol, or an    epoxide;-   each X is independently Cl, Br, or I; and-   each R^(a) is hydrogen, an alkyl group, or an aryl group;-   y is 0-2500;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur; and-   L² is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L² are independently replaced by -Cy-, —O—, —NR—, —S—, or    —C(O)—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur,-   and    (c) coupling the compound of formula II-e to one or more of the    hydroxyl groups on the metal surface.

Each of the L¹, y, W, and L² groups of formula II-e are as described inclasses and subclasses for compounds of formulae I and II, both singlyand in combination.

In other embodiments, the present invention provides a method forpreparing a covalently modified metal surface, comprising the steps of:

(a) modifying a metal substrate to incorporate thereon a plurality ofhydroxyl groups;(b) providing a compound of formula II-e; and(c) coupling the compound of formula II-e to one or more of the hydroxylgroups on the metal surface, further comprising the step of coupling theazide-terminal end to a suitable group via Click chemistry.

In other embodiments, the present invention provides a compound offormula II-e′:

or a salt thereof, wherein:

-   W is —Si(R^(a))₂OH, —Si(OR^(a))₂OH, —Si(R^(a))₂X, —Si(R^(a))(OH)₂,    —Si(R^(a))X₂, or —Si(OR^(a))₂X;-   each X is independently Cl, Br, or I; and-   each R^(a) is hydrogen, an alkyl group, or an aryl group;-   y is 0-2500;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur; and-   L² is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L² are independently replaced by -Cy-, —O—, —NR—, —S—, or    —C(O)—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur.

Each of the L¹, y, W, and L² groups of formula II-e′ are as described inclasses and subclasses for compounds of formulae I and II, both singlyand in combination.

In other embodiments, the R¹ group of formula I is a copolymer group.Multiblock copolymers of the present invention are prepared by methodsknown to one of ordinary skill in the art and those described in detailin U.S. patent application Ser. No. 11/325,020 filed Jan. 4, 2006, theentirety of which is hereby incorporated herein by reference. Accordingto another aspect, R¹ is a block copolymer group of formula III:

wherein:

-   y is 1-2500;-   m is 1 to 1000;-   m′ is 0 to 1000;-   R^(x) and R^(y) are each independently a natural or unnatural amino    acid side-chain group, wherein R^(x) and R^(y) are different from    each other;-   R² is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X′)₂, a 9-30 membered crown ether, a    mono-protected amine, a di-protected amine, a protected aldehyde, a    protected hydroxyl, a protected carboxylic acid, a protected thiol,    or an optionally substituted group selected from aliphatic, a 3-8    membered saturated, partially unsaturated, or aryl ring having 0-4    heteroatoms independently selected from nitrogen, oxygen, or sulfur,    an 8-10 membered saturated, partially unsaturated, or aryl bicyclic    ring having 0-5 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, or a detectable moiety;-   each X′ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur;-   Q is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of Q are independently replaced by -Cy-, —O—, —NH—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NHSO₂—, —SO₂NH—, —NHC(O)—,    —C(O)NH—, —OC(O)NH—, or —NHC(O)O—, wherein:    -   -Cy- is an optionally substituted 5-8 membered bivalent,        saturated, partially unsaturated, or aryl ring having 0-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur, or an optionally substituted 8-10 membered bivalent        saturated, partially unsaturated, or aryl bicyclic ring having        0-5 heteroatoms independently selected from nitrogen, oxygen, or        sulfur; and-   L³ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of Q are independently replaced by -Cy-, —O—, —NH—, —S—, or    —C(O)—, wherein:    -   -Cy- is an optionally substituted 5-8 membered bivalent,        saturated, partially unsaturated, or aryl ring having 0-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur, or an optionally substituted 8-10 membered bivalent        saturated, partially unsaturated, or aryl bicyclic ring having        0-5 heteroatoms independently selected from nitrogen, oxygen, or        sulfur.

In certain embodiments, the m′ group of formula III is 1-1000. Incertain embodiments, the m′ group of formula III is 0. In otherembodiments, m′ is 1-1000. According to other embodiments, m and m′ areindependently 10 to 100 repeat units. In still other embodiments, m is1-20 repeat units and m′ is 10-50 repeat units.

As defined generally above, the Q group of formula III is a valence bondor a bivalent, saturated or unsaturated, straight or branched C₁₋₁₂alkylene chain, wherein 0-6 methylene units of Q are independentlyreplaced by -Cy-, —O—, —NH—, —S—, —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—,—NHSO₂—, —SO₂NH—, —NHC(O)—, —C(O)NH—, —OC(O)NH—, or —NHC(O)O—, wherein-Cy- is an optionally substituted 5-8 membered bivalent, saturated,partially unsaturated, or aryl ring having 0-4 heteroatoms independentlyselected from nitrogen, oxygen, or sulfur, or an optionally substituted8-10 membered bivalent saturated, partially unsaturated, or arylbicyclic ring having 0-5 heteroatoms independently selected fromnitrogen, oxygen, or sulfur. In certain embodiments, Q is a valencebond. In other embodiments, Q is a bivalent, saturated C₁₋₁₂ alkylenechain, wherein 0-6 methylene units of Q are independently replaced by-Cy-, —O—, —NH—, —S—, —OC(O)—, —C(O)O—, or —C(O)—, wherein -Cy- is anoptionally substituted 5-8 membered bivalent, saturated, partiallyunsaturated, or aryl ring having 0-4 heteroatoms independently selectedfrom nitrogen, oxygen, or sulfur, or an optionally substituted 8-10membered bivalent saturated, partially unsaturated, or aryl bicyclicring having 0-5 heteroatoms independently selected from nitrogen,oxygen, or sulfur.

In certain embodiments, Q is -Cy- (i.e. a C₁ alkylene chain wherein themethylene unit is replaced by -Cy-), wherein -Cy- is an optionallysubstituted 5-8 membered bivalent, saturated, partially unsaturated, oraryl ring having 0-4 heteroatoms independently selected from nitrogen,oxygen, or sulfur. According to one aspect of the present invention,-Cy- is an optionally substituted bivalent aryl group. According toanother aspect of the present invention, -Cy- is an optionallysubstituted bivalent phenyl group. In other embodiments, -Cy- is anoptionally substituted 5-8 membered bivalent, saturated carbocyclicring. In still other embodiments, -Cy- is an optionally substituted 5-8membered bivalent, saturated heterocyclic ring having 1-2 heteroatomsindependently selected from nitrogen, oxygen, or sulfur. Exemplary -Cy-groups include bivalent rings selected from phenyl, pyridyl,pyrimidinyl, cyclohexyl, cyclopentyl, or cyclopropyl.

In certain embodiments, R^(x) is a crosslinkable amino acid side-chaingroup and R^(y) is a hydrophobic amino acid side-chain group. Suchcrosslinkable amino acid side-chain groups include tyrosine, serine,cysteine, threonine, aspartic acid (also known as aspartate, whencharged), glutamic acid (also known as glutamate, when charged),asparagine, histidine, lysine, arginine, and glutamine. Such hydrophobicamino acid side-chain groups include a suitably protected tyrosineside-chain, a suitably protected serine side-chain, a suitably protectedthreonine side-chain, phenylalanine, alanine, valine, leucine,tryptophan, proline, benzyl and alkyl glutamates, or benzyl and alkylaspartates or mixtures thereof. In other embodiments, R^(y) is an ionicamino acid side-chain group. Such ionic amino acid side chain groupsincludes a lysine side-chain, arginine side-chain, or a suitablyprotected lysine or arginine side-chain, an aspartic acid side chain,glutamic acid side-chain, or a suitably protected aspartic acid orglutamic acid side-chain. One of ordinary skill in the art wouldrecognize that protection of a polar or hydrophilic amino acidside-chain can render that amino acid nonpolar. For example, a suitablyprotected tyrosine hydroxyl group can render that tyrosine nonpolar andhydrophobic by virtue of protecting the hydroxyl group. Suitableprotecting groups for the hydroxyl, amino, and thiol, and carboylatefunctional groups of R^(x) and R^(y) are as described herein.

In other embodiments, R^(y) comprises a mixture of hydrophobic andhydrophilic amino acid side-chain groups such that the overallpoly(amino acid) block comprising R^(y) is hydrophobic. Such mixtures ofamino acid side-chain groups include phenylalanine/tyrosine,phenalanine/serine, leucine/tyrosine, and the like. According to anotherembodiment, R^(y) is a hydrophobic amino acid side-chain group selectedfrom phenylalanine, alanine, or leucine, and one or more of tyrosine,serine, or threonine.

As defined above, R^(x) is a natural or unnatural amino acid side-chaingroup capable of forming cross-links. It will be appreciated that avariety of amino acid side-chain functional groups are capable of suchcross-linking, including, but not limited to, carboxylate, hydroxyl,thiol, and amino groups. Examples of R^(x) moieties having functionalgroups capable of forming cross-links include a glutamic acidside-chain, —CH₂C(O)CH, an aspartic acid side-chain, —CH₂CH₂C(O)OH, acystein side-chain, —CH₂SH, a serine side-chain, —CH₂OH, an aldehydecontaining side-chain, —CH₂C(O)H, a lysine side-chain, —(CH₂)₄NH₂, anarginine side-chain, —(CH₂)₃NHC(═NH)NH₂, a histidine side-chain,—CH₂-imidazol-4-yl.

In certain embodiments, the present invention provides a method forpreparing a covalently modified metal surface, comprising the steps of:

(a) modifying a metal substrate to incorporate thereon a plurality ofhydroxyl groups;(b) providing a compound of formula III-a:

wherein:

-   W is —C(═O)OH, —C(═O)X, —P(═O)(OH)₂, —P(═O)(X)₂, —P(═O)(R^(a))OH,    —P(═O)(R^(a))X, —O—S(═O)₂OH, —S(═O)₂OH, —Si(R^(a))₂OH,    —Si(OR^(a))₂OH, —Si(R^(a))₂X, —Si(R^(a))(OH)₂, —Si(R^(a))X₂,    —Si(OR^(a))₂X, C(═O)H, —N═C═S, —N═C═O, phenol, thiophenol, or an    epoxide;-   each X is independently Cl, Br, or I; and-   each R^(a) is hydrogen, an alkyl group, or an aryl group;-   y is 1-2500;-   m is 1 to 1000;-   m′ is 0 to 1000;-   R^(x) and R^(y) are each independently a natural or unnatural amino    acid side-chain group, wherein R^(x) and R^(y) are different from    each other;-   R² is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X′)₂, a 9-30 membered crown ether, a    mono-protected amine, a di-protected amine, a protected aldehyde, a    protected hydroxyl, a protected carboxylic acid, a protected thiol,    or an optionally substituted group selected from aliphatic, a 3-8    membered saturated, partially unsaturated, or aryl ring having 0-4    heteroatoms independently selected from nitrogen, oxygen, or sulfur,    an 8-10 membered saturated, partially unsaturated, or aryl bicyclic    ring having 0-5 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, or a detectable moiety;-   each X′ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur;-   Q is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of Q are independently replaced by -Cy-, —O—, —NH—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NHSO₂—, —SO₂NH—, —NHC(O)—,    —C(O)NH—, —OC(O)NH—, or —NHC(O)O—, wherein:    -   -Cy- is an optionally substituted 5-8 membered bivalent,        saturated, partially unsaturated, or aryl ring having 0-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur, or an optionally substituted 8-10 membered bivalent        saturated, partially unsaturated, or aryl bicyclic ring having        0-5 heteroatoms independently selected from nitrogen, oxygen, or        sulfur; and-   L³ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of Q are independently replaced by -Cy-, —O—, —NH—, —S—, or    —C(O)—, wherein:    -   -Cy- is an optionally substituted 5-8 membered bivalent,        saturated, partially unsaturated, or aryl ring having 0-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur, or an optionally substituted 8-10 membered bivalent        saturated, partially unsaturated, or aryl bicyclic ring having        0-5 heteroatoms independently selected from nitrogen, oxygen, or        sulfur;-   and    (c) coupling the compound of formula III-a to one or more of the    hydroxyl groups on the metal surface.

Each of the R², L¹, y, m, m′, Q, R^(x), R^(y), and L³ groups of formulaIII-a are as described in classes and subclasses for compounds offormulae II and III, both singly and in combination.

In certain embodiments, the present invention provides a method forpreparing a covalently modified metal surface, comprising the steps of:

(a) modifying a metal substrate to incorporate thereon a plurality ofhydroxyl groups;(b) providing a compound of formula III-b:

wherein:

-   y is 1-2500;-   m is 1 to 1000;-   m′ is 0 to 1000;-   R^(x) and R^(y) are each independently a natural or unnatural amino    acid side-chain group, wherein R^(x) and R^(y) are different from    each other;-   R² is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X′)₂, a 9-30 membered crown ether, a    mono-protected amine, a di-protected amine, a protected aldehyde, a    protected hydroxyl, a protected carboxylic acid, a protected thiol,    or an optionally substituted group selected from aliphatic, a 3-8    membered saturated, partially unsaturated, or aryl ring having 0-4    heteroatoms independently selected from nitrogen, oxygen, or sulfur,    an 8-10 membered saturated, partially unsaturated, or aryl bicyclic    ring having 0-5 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, or a detectable moiety;-   each X′ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur;-   Q is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of Q are independently replaced by -Cy-, —O—, —NH—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NHSO₂—, —SO₂NH—, —NHC(O)—,    —C(O)NH—, —OC(O)NH—, or —NHC(O)O—, wherein:    -   -Cy- is an optionally substituted 5-8 membered bivalent,        saturated, partially unsaturated, or aryl ring having 0-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur, or an optionally substituted 8-10 membered bivalent        saturated, partially unsaturated, or aryl bicyclic ring having        0-5 heteroatoms independently selected from nitrogen, oxygen, or        sulfur; and-   L³ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of Q are independently replaced by -Cy-, —O—, —NH—, —S—, or    —C(O)—, wherein:    -   -Cy- is an optionally substituted 5-8 membered bivalent,        saturated, partially unsaturated, or aryl ring having 0-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur, or an optionally substituted 8-10 membered bivalent        saturated, partially unsaturated, or aryl bicyclic ring having        0-5 heteroatoms independently selected from nitrogen, oxygen, or        sulfur;-   and    (c) coupling the compound of formula III-b to one or more of the    hydroxyl groups on the metal surface by dehydration reaction.

Each of the R², L¹, y, m, m′, Q, R^(x), R^(y), and L³ groups of formulaIII-b are as described in classes and subclasses for compounds offormula III, both singly and in combination.

In certain embodiments, the present invention provides a method forpreparing a covalently modified metal surface, comprising the steps of:

(a) modifying a metal substrate to incorporate thereon a plurality ofhydroxyl groups;(b) providing a compound of formula III-c:

wherein:

-   y is 10-2500;-   m is 1 to 1000;-   m′ is 0 to 1000;-   R^(x) and R^(y) are each independently a natural or unnatural amino    acid side-chain group, wherein R^(x) and R^(y) are different from    each other;-   R² is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X′)₂, a 9-30 membered crown ether, a    mono-protected amine, a di-protected amine, a protected aldehyde, a    protected hydroxyl, a protected carboxylic acid, a protected thiol,    or an optionally substituted group selected from aliphatic, a 3-8    membered saturated, partially unsaturated, or aryl ring having 0-4    heteroatoms independently selected from nitrogen, oxygen, or sulfur,    an 8-10 membered saturated, partially unsaturated, or aryl bicyclic    ring having 0-5 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, or a detectable moiety;-   each X′ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur;-   Q is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of Q are independently replaced by -Cy-, —O—, —NH—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NHSO₂—, —SO₂NH—, —NHC(O)—,    —C(O)NH—, —OC(O)NH—, or —NHC(O)O—, wherein:    -   -Cy- is an optionally substituted 5-8 membered bivalent,        saturated, partially unsaturated, or aryl ring having 0-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur, or an optionally substituted 8-10 membered bivalent        saturated, partially unsaturated, or aryl bicyclic ring having        0-5 heteroatoms independently selected from nitrogen, oxygen, or        sulfur; and-   L³ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of Q are independently replaced by -Cy-, —O—, —NH—, —S—, or    —C(O)—, wherein:    -   -Cy- is an optionally substituted 5-8 membered bivalent,        saturated, partially unsaturated, or aryl ring having 0-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur, or an optionally substituted 8-10 membered bivalent        saturated, partially unsaturated, or aryl bicyclic ring having        0-5 heteroatoms independently selected from nitrogen, oxygen, or        sulfur;-   and    (c) coupling the compound of formula III-c to one or more of the    hydroxyl groups on the metal surface by dehydration reaction.

Each of the R², L¹, y, m, m′, Q, R^(x), R^(y), and L³ groups of formulaIII-c are as described in classes and subclasses for compounds offormula III, both singly and in combination.

In other embodiments, R¹ is a block copolymer group of formula IV:

wherein:

-   y is 10-2500;-   m is 1 to 1000;-   m′ is 0 to 1000;-   R^(x) and R^(y) are each independently a natural or unnatural amino    acid side-chain group, wherein R^(x) and R^(y) are different from    each other;-   R² is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X′)₂, a 9-30 membered crown ether, a    mono-protected amine, a di-protected amine, a protected aldehyde, a    protected hydroxyl, a protected carboxylic acid, a protected thiol,    or an optionally substituted group selected from aliphatic, a 3-8    membered saturated, partially unsaturated, or aryl ring having 0-4    heteroatoms independently selected from nitrogen, oxygen, or sulfur,    an 8-10 membered saturated, partially unsaturated, or aryl bicyclic    ring having 0-5 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, or a detectable moiety;-   each X′ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L¹ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L¹ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur;-   Q is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of Q are independently replaced by -Cy-, —O—, —NH—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NHSO₂—, —SO₂NH—, —NHC(O)—,    —C(O)NH—, —OC(O)NH—, or —NHC(O)O—, wherein:    -   -Cy- is an optionally substituted 5-8 membered bivalent,        saturated, partially unsaturated, or aryl ring having 0-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur, or an optionally substituted 8-10 membered bivalent        saturated, partially unsaturated, or aryl bicyclic ring having        0-5 heteroatoms independently selected from nitrogen, oxygen, or        sulfur; and-   L² is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of Q are independently replaced by -Cy-, —O—, —NH—, —S—, or    —C(O)—, wherein:    -   -Cy- is an optionally substituted 5-8 membered bivalent,        saturated, partially unsaturated, or aryl ring having 0-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur, or an optionally substituted 8-10 membered bivalent        saturated, partially unsaturated, or aryl bicyclic ring having        0-5 heteroatoms independently selected from nitrogen, oxygen, or        sulfur;-   R^(2a) is a mono-protected amine, a di-protected amine, —NHR³,    —N(R³)₂, —NHC(O)R³, —NR³C(O)R³, —NHC(O)NHR³, —NHC(O)N(R³)₂,    —NR³C(O)NHR³, —NR³C(O)N(R³)₂, —NHC(O)OR³, —NR³C(O)OR³, —NHSO₂R³, or    —NR³SO₂R³; and-   each R³ is independently an optionally substituted group selected    from aliphatic, a 5-8 membered saturated, partially unsaturated, or    aryl ring having 0-4 heteroatoms independently selected from    nitrogen, oxygen, or sulfur, an 8-10-membered saturated, partially    unsaturated, or aryl bicyclic ring having 0-5 heteroatoms    independently selected from nitrogen, oxygen, or sulfur, or a    detectable moiety, or:    -   two R³ on the same nitrogen atom are taken together with said        nitrogen atom to form an optionally substituted 4-7 membered        saturated, partially unsaturated, or aryl ring having 1-4        heteroatoms independently selected from nitrogen, oxygen, or        sulfur.

Each of the R², L¹, y, m, m′, Q, R^(x), R^(y), and L² groups of formulaIV are as described in classes and subclasses for compounds of formulaeII and III, both singly and in combination.

As defined generally above, the R^(2a) group of formula IV is amono-protected amine, a di-protected amine, —NHR³, —N(R³)₂, —NHC(O)R³,—NR³C(O)R³, —NHC(O)NHR³, —NHC(O)N(R³)₂, —NR³C(O)NHR³, —NR³C(O)N(R³)₂,—NHC(O)OR³, —NR³C(O)OR³, —NHSO₂R³, or —NR³SO₂R³, wherein each R³ isindependently an optionally substituted group selected from aliphatic, a5-8 membered saturated, partially unsaturated, or aryl ring having 0-4heteroatoms independently selected from nitrogen, oxygen, or sulfur, an8-10-membered saturated, partially unsaturated, or aryl bicyclic ringhaving 0-5 heteroatoms independently selected from nitrogen, oxygen, orsulfur, or a detectable moiety, or two R³ on the same nitrogen atom aretaken together with said nitrogen atom to form an optionally substituted4-7 membered saturated, partially unsaturated, or aryl ring having 1-4heteroatoms independently selected from nitrogen, oxygen, or sulfur.

In certain embodiments, the R^(2a) group of formula IV is —NHR³ or—N(R³)₂ wherein each R³ is an optionally substituted aliphatic group.One exemplary R³ group is 5-norbornen-2-yl-methyl. According to yetanother aspect of the present invention, the R^(2a) group of formula IVis —NHR³ wherein R³ is a C₁₋₆ aliphatic group substituted with N₃.Examples include —CH₂N₃. In some embodiments, R³ is an optionallysubstituted C₁₋₆ alkyl group. Examples include methyl, ethyl, propyl,butyl, pentyl, hexyl, 2-(tetrahydropyran-2-yloxy)ethyl,pyridin-2-yldisulfanylmethyl, methyldisulfanylmethyl,(4-acetylenylphenyl)methyl, 3-(methoxycarbonyl)-prop-2-ynyl,methoxycarbonylmethyl,2-(N-methyl-N-(4-acetylenylphenyl)carbonylamino)-ethyl,2-phthalimidoethyl, 4-bromobenzyl, 4-chlorobenzyl, 4-fluorobenzyl,4-iodobenzyl, 4-propargyloxybenzyl, 2-nitrobenzyl,4-(bis-4-acetylenylbenzyl)aminomethyl-benzyl, 4-propargyloxy-benzyl,4-dipropargylamino-benzyl, 4-(2-propargyloxy-ethyldisulfanyl)benzyl,2-propargyloxy-ethyl, 2-propargyldisulfanyl-ethyl, 4-propargyloxy-butyl,2-(N-methyl-N-propargylamino)ethyl, and2-(2-dipropargylaminoethoxy)-ethyl. In other embodiments, R³ is anoptionally substituted C₂₋₆ alkenyl group. Examples include vinyl,allyl, crotyl, 2-propenyl, and but-3-enyl. When R³ group is asubstituted aliphatic group, suitable substituents on R³ include N₃, CN,and halogen. In certain embodiments, R³ is —CH₂CN, —CH₂CH₂CN,—CH₂CH(OCH₃)₂, 4-(bisbenzyloxymethyl)phenylmethyl, and the like.

According to another aspect of the present invention, the R^(2a) groupof formula IV is —NHR³ wherein R³ is an optionally substituted C₂₋₆alkynyl group. Examples include —CC≡CH, —CH₂C≡CH, —CH₂C≡CCH₃, and—CH₂CH₂C≡CH.

In certain embodiments, the R^(2a) group of formula IV is —NHR³ whereinR³ is an optionally substituted 5-8-membered aryl ring. In certainembodiments, R³ is optionally substituted phenyl or optionallysubstituted pyridyl. Examples include phenyl,4-t-butoxycarbonylaminophenyl, 4-azidomethylphenyl,4-propargyloxyphenyl, 2-pyridyl, 3-pyridyl, and 4-pyridyl. In certainembodiments, R^(2a) is 4-t-butoxycarbonylaminophenylamino,4-azidomethylphenamino, or 4-propargyloxyphenylamino.

In certain embodiments, the R^(2a) group of formula IV is —NHR³ whereinR³ is an optionally substituted phenyl ring. Suitable substituents onthe R³ phenyl ring include halogen; —(CH₂)₀₋₄R^(o); —(CH₂)₀₋₄OR^(o);—(CH₂)₀₋₄CH(OR^(o))₂; —(CH₂)₀₋₄SR^(o); —(CH₂)₀₋₄Ph, which may besubstituted with R^(o); —(CH₂)₀₋₄O(CH₂)₀₋₁Ph which may be substitutedwith R^(o); —CH═CHPh, which may be substituted with R^(o); —NO₂; —CN;—N₃; —(CH₂)₀₋₄N(R^(o))₂; —(CH₂)₀₋₄N(R^(o))C(O)R^(o); —N(R^(o))C(S)R^(o);—(CH₂)₀₋₄N(R^(o))C(O)NR^(o) ₂; —N(R^(o))C(S)NR^(o) ₂;—(CH₂)₀₋₄N(R^(o))C(O)OR^(o); —N(R^(o))N(R^(o))C(O)R^(o);—N(R^(o))N(R^(o))C(O)NR^(o) ₂; —N(R^(o))N(R^(o))C(O)OR^(o);—(CH₂)₀₋₄C(O)R^(o); —C(S)R^(o); —(CH₂)₀₋₄C(O)OR^(o);—(CH₂)₀₋₄C(O)SR^(o); —(CH₂)₀₋₄C(O)OSiR^(o) ₃; —(CH₂)₀₋₄OC(O)R^(o);—(CH₂)₀₋₄SC(O)R^(o); —(CH₂)₀₋₄C(O)NR^(o) ₂; —C(S)NR^(o) ₂;—(CH₂)₀₋₄OC(O)NR^(o) ₂; —C(O)N(OR^(o))R^(o); —C(O)C(O)R^(o);—C(O)CH₂C(O)R^(o); —C(NOR^(o))R^(o); —(CH₂)₀₋₄SSR^(o);—(CH₂)₀₋₄S(O)₂R^(o); —(CH₂)₀₋₄S(O)₂OR^(o); —(CH₂)₀₋₄O(O)₂R^(o);—S(O)₂NR^(o) ₂; —(CH₂)₀₋₄(O)R^(o); —N(R^(o))S(O)₂NR^(o) ₂;—N(R^(o))S(O)₂R^(o); —N(OR^(o))R^(o); —C(NH)NR^(o) ₂; —P(O)₂R^(o);—P(O)R^(o) ₂; —OP(O)R^(o) ₂; SiR^(o) ₃; wherein each independentoccurrence of R^(o) is as defined herein supra. In other embodiments,the R^(2a) group of formula IV is —NHR³ wherein R³ is phenyl substitutedwith one or more optionally substituted C₁₋₆ aliphatic groups. In stillother embodiments, R³ is phenyl substituted with vinyl, allyl,acetylenyl, —CH₂N₃, —CH₂CH₂N₃, —CH₂C≡CCH₃, or —CH₂C≡CH.

In certain embodiments, the R^(2a) group of formula IV is —NHR³ whereinR³ is phenyl substituted with N₃, N(R^(o))₂, CO₂R^(o), or C(O)R^(o)wherein each R^(o) is independently as defined herein supra.

In certain embodiments, the R^(2a) group of formula IV is —N(R³)₂wherein each R³ is independently an optionally substituted groupselected from aliphatic, phenyl, naphthyl, a 5-6 membered aryl ringhaving 1-4 heteroatoms independently selected from nitrogen, oxygen, orsulfur, or a 8-10 membered bicyclic aryl ring having 1-5 heteroatomsindependently selected from nitrogen, oxygen, or sulfur, or a detectablemoiety.

In other embodiments, the R^(2a) group of formula IV is —N(R³)₂ whereinthe two R³ groups are taken together with said nitrogen atom to form anoptionally substituted 4-7 membered saturated, partially unsaturated, oraryl ring having 1-4 heteroatoms independently selected from nitrogen,oxygen, or sulfur. According to another embodiment, the two R³ groupsare taken together to form a 5-6-membered saturated or partiallyunsaturated ring having one nitrogen wherein said ring is substitutedwith one or two oxo groups. Such R^(2a) groups include, but are notlimited to, phthalimide, maleimide and succinimide.

In certain embodiments, the R^(2a) group of formula IV is amono-protected or di-protected amino group. In certain embodimentsR^(2a) is a mono-protected amine. In certain embodiments R^(2a) is amono-protected amine selected from aralkylamines, carbamates, allylamines, or amides. Examplary mono-protected amino moieties includet-butyloxycarbonylamino, ethyloxycarbonylamino, methyloxycarbonylamino,trichloroethyloxy-carbonylamino, allyloxycarbonylamino,benzyloxocarbonylamino, allylamino, benzylamino,fluorenylmethylcarbonyl, formamido, acetamido, chloroacetamido,dichloroacetamido, trichloroacetamido, phenylacetamido,trifluoroacetamido, benzamido, and t-butyldiphenylsilylamino. In otherembodiments R^(2a) is a di-protected amine. Exemplary di-protected aminomoieties include di-benzylamino, di-allylamino, phthalimide, maleimido,succinimido, pyrrolo, 2,2,5,5-tetramethyl-[1,2,5]azadisilolidino, andazido. In certain embodiments, the R^(2a) moiety is phthalimido. Inother embodiments, the R^(2a) moiety is mono- or di-benzylamino or mono-or di-allylamino.

In certain embodiments, the R^(2a) group of formula IV comprises a groupsuitable for Click chemistry. One of ordinary skill in the art wouldrecognize that certain R^(2a) groups of the present invention aresuitable for Click chemistry.

Compounds of formula IV having R^(2a) groups comprising groups suitablefor Click chemistry are useful for conjugating said compounds tobiological systems such as proteins, viruses, and cells, to name but afew. Thus, another embodiment of the present invention provides a methodof conjugating the R^(2a) group of a compound of formula IV to amacromolecule via Click chemistry. Yet another embodiment of the presentinvention provides a macromolecule conjugated to a compound of formulaIV via the R^(2a) group.

According to one embodiment, the R^(2a) group of formula IV is anazide-containing group. According to another embodiment, the R^(2a)group of formula IV is an alkyne-containing group.

In certain embodiments, the R^(2a) group of formula IV has a terminalalkyne moiety. In other embodiments, the R^(2a) group of formula IV isan alkyne-containing moiety having an electron withdrawing group.Accordingly, in such embodiments, the R^(2a) group of formula IV is

wherein E is an electron withdrawing group and y is 0-6. Such electronwithdrawing groups are known to one of ordinary skill in the art. Incertain embodiments, E is an ester. In other embodiments, the R^(2a)group of formula IV is

wherein E is an electron withdrawing group, such as a —C(O)O— group andy is 0-6.

According to another embodiment, the present invention providescompounds of formula IV, as described above, wherein said compounds havea polydispersity index (“PDI”) of about 1.0 to about 1.2. According toanother embodiment, the present invention provides compounds of formulaIV, as described above, wherein said compound has a polydispersity index(“PDI”) of about 1.03 to about 1.15. According to yet anotherembodiment, the present invention provides compounds of formula IV, asdescribed above, wherein said compound has a polydispersity index(“PDI”) of about 1.10 to about 1.12. According to other embodiments, thepresent invention provides compounds of formula IV having a PDI of lessthan about 1.10.

In certain embodiments, the present invention provides compounds offormula IV, as described above, wherein n is about 225. In otherembodiments, n is about 200 to about 300. In still other embodiments, nis about 200 to about 250. In still other embodiments, n is about 100 toabout 150. In still other embodiments, n is about 400 to about 500.

Exemplary R^(2a) groups of formula IV are set forth in Table 1, below.

TABLE 1 Representative R^(2a) Groups

i

ii

iii

iv

v

vi

vii

viii

ix

x

x

xi

xii

xiii

xiv

xv

xvi

xvii

xviii

xix

xx

xxi

xxii

xxiii

xxiv

xxv

xxvi

xxvii

xxviii

xxix

xxx

xxxi

xxxii

xxxiii

xxxiv

xxxv

xxxvi

xxxvii

xxxviii

xxxix

xl

xli

xlii

xliii

xliv

xlv

xlvi

xlvii

In certain embodiments, the R^(2a) group of formula IV is selected fromany of those R^(2a) groups depicted in Table 1, supra. In otherembodiments, the R^(2a) group of formula IV is group v, viii, xvi, xix,xxii, xxx, xxxi, xxxii, xxxiii, xxxiv, xxxv, xxxvi, xxxvii, or xlii. Inyet other embodiments, the R^(2a) group of formula IV is xv, xviii, xx,xxi, xxxviii, or xxxix.

Small Molecule Organic Groups

As defined generally above, R¹ is, inter alia, a small molecule organicgroup. In certain embodiments, R¹ is selected from monosaccharides(e.g., glucose, galactose, or fructose) disaccharides (e.g., sucrose,lactose, or maltose), phosphorylcholines, phosoplipids, cyclodextran,small molecule drugs, optionally substituted aliphatic groups,optionally substituted cyclic groups, detectable moieties, and the like.

In certain embodiments, R¹ is a group of formula V:

-   R⁴ is hydrogen, halogen, NO₂, CN, N₃, —N═C═O, —C(R)═NN(R)₂,    —P(O)(OR)₂, —P(O)(X″)₂, a 9-30 membered crown ether, a small    molecule drug, or an optionally substituted group selected from    aliphatic, a 3-8 membered saturated, partially unsaturated, or aryl    ring having 0-4 heteroatoms independently selected from nitrogen,    oxygen, or sulfur, an 8-10 membered saturated, partially    unsaturated, or aryl bicyclic ring having 0-5 heteroatoms    independently selected from nitrogen, oxygen, or sulfur, or a    detectable moiety;-   each X″ is independently halogen;-   each R is independently hydrogen or an optionally substituted    aliphatic group;-   L⁴ is a valence bond or a bivalent, saturated or unsaturated,    straight or branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene    units of L⁴ are independently replaced by -Cy-, —O—, —NR—, —S—,    —OC(O)—, —C(O)O—, —C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—,    —C(O)NR—, —OC(O)NR—, or —NRC(O)O—, wherein:    -   each -Cy- is independently an optionally substituted 3-8        membered bivalent, saturated, partially unsaturated, or aryl        ring having 0-4 heteroatoms independently selected from        nitrogen, oxygen, or sulfur, or an optionally substituted 8-10        membered bivalent saturated, partially unsaturated, or aryl        bicyclic ring having 0-5 heteroatoms independently selected from        nitrogen, oxygen, or sulfur.

In other embodiments, the R¹ group of formula I or the R⁴ group offormula V is a small molecule drug. For formula I, it is contemplatedthat the small molecule drug is either bonded directly to W or through alinker group L⁵, wherein L⁵ is as defined for the L² group of formula IIand in classes and subclasses described for L² herein. In certainembodiments, the linker group L⁴ or L⁵ is a hydrolytically cleavablelinker group. It will be appreciated that when the R¹ group of formula Ior the R⁴ group of formula V is a small molecule drug and thecorresponding L⁴ or L⁵ linker group is a hydrolytically cleavable linkergroup, then the small molecule drug can be slowly released by the metalsurface covalently modified therewith, upon, for example, implantationinto a patient. Such hydrolytically cleavable linker groups are wellknown to one or ordinary skill in the art.

In certain embodiments, the small molecule drug is a member of thetaxane family of anti-tubulin agents. In other embodiments, the smallmolecule drug is paclitaxel. In still other embodiments, the smallmolecule drug is docetaxel. In certain embodiments, the small moleculedrug is a member of the anthracyline family of cytotoxic agents. Inother embodiments, the small molecule drug is doxorubicin. In stillother embodiments, the small molecule drug is daunorubicin. In stillother embodiments, the small molecule drug is epirubicin.

In other embodiments, the R¹ group of formula I or the R⁴ group offormula V is an antithrombogenic oligopeptide. Such antithrombogenicoligopeptide are well known in the art and include sequences such asCys-Pro-Arg, Cys-(L)Phe-Pro-Arg, and/or Cys-(D)Phe-Pro-Arg.

It will also be appreciated that the R² group of formula II can be anantithromobgenic oligopeptide, such as those name above, attached to PEGvia a hydrolytically stable linkage.

In other embodiments, the R¹ group of formula I or the R⁴ group offormula V is a cell-binding oligopeptide. Cell-binding oligopeptides arewell known in the art and include α_(v)β₃ and α_(v)β₅ integrin bindingpeptide sequences such as those containing the Arg-Gly-Asp (RGD) andAsn-Gly-Arg (NGR) oligopeptide sequences. In one embodiment, the R¹group of formula I or the R⁴ group of formula V is the cell-bindingoligopeptide GRGDS. In another embodiment, the oligopeptide sequence isa cyclic RGD sequence such as c(RGDfK).

It will also be appreciated that the R² group of formula II can be acell-binding oligopeptide, such as those name above, attached to PEG viaa hydrolytically stable linkage.

It will also be appreciated that when the R² group of formula II is asmall molecule drug attached to the PEG via a hydrolytically cleavablelinker group, then that small molecule drug is slowly released by themetal surface covalently modified therewith leaving the PEGylated metalsurface. In certain embodiments, the small molecule drug connected toPEG via a hydrolytically cleavable linker is a member of the taxanefamily of anti-tubulin agents. In other embodiments, the small moleculedrug connected to PEG via a hydrolytically cleavable linker ispaclitaxel. In still other embodiments, the small molecule drugconnected to PEG via a hydrolytically cleavable linker is docetaxel.

It will also be appreciated that when the polymers of formula III areused for surface modification, a hydrophobic small molecule drug can beencapsulated in the hydrophobic region of polymer layer. Suchencapsulated small molecule drugs can be slowly released by thediffusion from the polymer layer. In certain embodiments, theencapsulated small molecule drug is a member of the taxane family ofanti-tubulin agents. In other embodiments, the encapsulated smallmolecule drug is paclitaxel. In still other embodiments, theencapsulated small molecule drug is docetaxel.

When the polymers of formula III are used for surface modification andencapsulation of a hydrophobic small molecule drug, the R^(x) groups ofthe polymer layer may be optionally crosslinked to control the diffusionof the encapsulated drug. Such crosslinking chemistry is well known inthe art and includes such methods described in detail in United Statespatent application publication number US20060240092, the entirety ofwhich is hereby incorporated herein by reference. Such encapsulatedsmall molecule drugs can be released in a controlled fashion over longertime periods compared to release by diffusion alone. In certainembodiments, the encapsulated small molecule drug is a member of thetaxane family of anti-tubulin agents. In other embodiments, theencapsulated small molecule drug is paclitaxel. In still otherembodiments, the encapsulated small molecule drug is docetaxel.

Small molecule drugs suitable as R¹, R², and R⁴ groups of the presentcompounds include, but are not limited to, those having a functionalgroup, or can be modified to include a functional group, suitable forcovalently linking to one or more hydroxyl groups incorporated onto themetal substrate. As described herein, such drugs can be linked directlyor via a hydrolytically cleavable linker. Such drugs include, withoutlimitation, chemotherapeutic agents or other anti-proliferative agentsincluding alkylating drugs (mechlorethamine, chlorambucil,Cyclophosphamide, Melphalan, Ifosfamide), antimetabolites(Methotrexate), purine antagonists and pyrimidine antagonists(6-Mercaptopurine, 5-Fluorouracil, Cytarabile, Gemcitabine), spindlepoisons (Vinblastine, Vincristine, Vinorelbine, Paclitaxel),podophyllotoxins (Etoposide, Irinotecan, Topotecan), antibiotics(Doxorubicin, Bleomycin, Mitomycin), nitrosoureas (Carmustine,Lomustine), inorganic ions (Cisplatin, Carboplatin), enzymes(Asparaginase), angiogenesis inhibitors (Avastin) and hormones(Tamoxifen, Leuprolide, Flutamide, and Megestrol), Gleevec,dexamethasone, and cyclophosphamide. For a more comprehensive discussionof updated cancer therapies see, http://www.nci.nih.gov/, a list of theFDA approved oncology drugs athttp://www.fda.gov/cder/cancer/druglistframe.htm, and The Merck Manual,Seventeenth Ed. 1999, the entire contents of which are herebyincorporated by reference.

In other embodiments, the chemotherapeutic agent is Exemestance(aromasin), Camptosar (irinotecan), Ellence (epirubicin), Femara(Letrozole), Gleevac (imatinib mesylate), Lentaron (formestane),Cytadren/Orimeten (aminoglutethimide), Temodar, Proscar (finasteride),Viadur (leuprolide), Nexavar (Sorafenib), Kytril (Granisetron), Taxotere(Docetaxel), Taxol (paclitaxel), Kytril (Granisetron), Vesanoid(tretinoin) (retin A), XELODA (Capecitabine), Arimidex (Anastrozole),Casodex/Cosudex (Bicalutamide), Faslodex (Fulvestrant), Iressa(Gefitinib), Nolvadex, Istubal, Valodex (tamoxifen citrate), Tomudex(Raltitrexed), Zoladex (goserelin acetate), Leustatin (Cladribine),Velcade (bortezomib), Mylotarg (gemtuzumab ozogamicin), Alimta(pemetrexed), Gemzar (gemcitabine hydrochloride), Rituxan (rituximab),Revlimid (lenalidomide), Thalomid (thalidomide), Alkeran (melphalan),and derivatives thereof.

Other exemplary small molecule drugs include analgesics,anti-inflammatory agents, antihelminthics, anti-arrhythmic agents,anti-bacterial agents, anti-viral agents, anti-coagulants,anti-depressants, anti-diabetics, anti-epileptics, anti-fungal agents,anti-gout agents, anti-hypertensive agents, anti-malarials,anti-migraine agents, anti-muscarinic agents, anti-neoplastic agents,erectile dysfunction improvement agents, immunosuppressants,anti-protozoal agents, anti-thyroid agents, anxiolytic agents,sedatives, hypnotics, neuroleptics, β-blockers, cardiac inotropicagents, corticosteroids, diuretics, anti-parkinsonian agents,gastro-intestinal agents, histamine receptor antagonists, keratolyptics,lipid regulating agents, anti-anginal agents, Cox-2 inhibitors,leukotriene inhibitors, macrolides, muscle relaxants, nutritionalagents, opiod analgesics, protease inhibitors, sex hormones, stimulants,muscle relaxants, anti-osteoporosis agents, anti-obesity agents,cognition enhancers, anti-urinary incontinence agents, anti-benignprostate hypertrophy agents, essential fatty acids, non-essential fattyacids, and mixtures thereof.

Other examples of small molecule drugs include treatments forAlzheimer's Disease such as Aricept® and Excelon®; treatments forParkinson's Disease such as L-DOPA/carbidopa, entacapone, ropinrole,pramipexole, bromocriptine, pergolide, trihexephendyl, and amantadine;agents for treating Multiple Sclerosis (MS) such as beta interferon(e.g., Avonex® and Rebif®), Copaxone®, and mitoxantrone; treatments forasthma such as albuterol and Singulair®; agents for treatingschizophrenia such as zyprexa, risperdal, seroquel, and haloperidol;anti-inflammatory agents such as corticosteroids, TNF blockers, IL-1 RA,azathioprine, cyclophosphamide, and sulfasalazine; immunomodulatory andimmunosuppressive agents such as cyclosporin, tacrolimus, rapamycin,mycophenolate mofetil, interferons, corticosteroids, cyclophosphamide,azathioprine, and sulfasalazine; neurotrophic factors such asacetylcholinesterase inhibitors, MAO inhibitors, interferons,anti-convulsants, ion channel blockers, riluzole, and anti-Parkinsonianagents; agents for treating cardiovascular disease such asbeta-blockers, ACE inhibitors, diuretics, nitrates, calcium channelblockers, and statins; agents for treating liver disease such ascorticosteroids, cholestyramine, interferons, and anti-viral agents;agents for treating blood disorders such as corticosteroids,anti-leukemic agents, and growth factors; and agents for treatingimmunodeficiency disorders such as gamma globulin.

In other embodiments, the R¹ group of formula I or the R⁴ group offormula V is a small molecule blood-compatibilizing agent. Suchblood-compatibilizing agents are well known in the art and includephosphorylchoine and phosphorylcholine derivatives.

It will also be appreciated that the R² group of formula II can be asmall molecule blood-compatibilizing agent attached to the PEG via ahydrolytically stable linkage. In certain embodiments, the R² group isphosphorylchoine or a phosphorylcholine derivative.

Exemplary R¹ groups are set forth in Table 2, below.

TABLE 2 Representative R¹ Groups

i

ii

iii

iv

v

vi

vii

viii

ix

x

xi

xii

xiii

xiv

xv

xvi

xvii

xviii

xix

xx

xxi

xxii

xxiii

xxiv

xxv

xxvi

xxvii

xxviii

xxix

xxx

xxxi

xxxii

xxxiii

xxxiv

xxxv

xxxvi

xxxvii

xxxviii

xxxix

xxxx

xxxxi

xxxxii

xxxxiii

xxxxiv

xxxxv wherein each y, m, and m′ is as defined above and describedherein.

Additional exemplary R¹ groups are set forth in Table 3, below.

TABLE 3 Representative R¹ Groups

xii

xiii

xiv

xv

xvi

xvii

xviii

xix

xx

xxi

xxii wherein each y is as defined above and described herein.

Exemplary R^(a) groups are set forth in Table 4, below.

TABLE 4 Exemplary R^(a) Groups

a - - - -CH₃ b

c

d

e

Exemplary R² groups are set forth in Table 5, below.

TABLE 5 Exemplary R2 Groups

a

b

c

d

e

f

g

h

i

j

k

l - - - -CH₃ m

4. General Methods for Providing Compounds of the Present Invention

Multiblock copolymers of the present invention are prepared by methodsknown to one of ordinary skill in the art and those described in detailin U.S. patent application Ser. No. 11/325,020 filed Jan. 4, 2006, theentirety of which is hereby incorporated herein by reference. Generally,such multiblock copolymers are prepared by sequentially polymerizing oneor more cyclic amino acid monomers onto a hydrophilic polymer having aterminal amine salt wherein said polymerization is initiated by saidamine salt. In certain embodiments, said polymerization occurs byring-opening polymerization of the cyclic amino acid monomers. In otherembodiments, the cyclic amino acid monomer is an amino acid NCA, lactam,or imide.

Scheme 1 above depicts a general method for preparing multiblockpolymers of the R¹ group of formula I of the present invention. Amacroinitiator of formula A is treated with a first amino acid NCA toform a compound of formula B having a first amino acid block. The secondamino acid NCA is added to the living polymer of formula B to form acompound of formula III-a having two differing amino acid blocks. Eachof the R², L¹, A, y, Q, R^(x), R^(y), m, and m′ groups depicted inScheme 1 are as defined and described in classes and subclasses, singlyand in combination, herein.

Scheme 2 above shows one exemplary method for preparing the bifunctionalPEGs used to prepare the multiblock copolymers of the present invention.As described in United States patent application publication numberUS20060142506, suitably protected PEG-amines may be formed byterminating the living polymer chain end of a PEG with a terminatingagent that contains a suitably protected amine. The suitably protectedamine may then be deprotected to generate a PEG that is terminated witha free amine that may subsequently be converted into the correspondingPEG-amine salt macroinitiator. In certain embodiments, the PEG-aminesalt macroinitiator of the present invention is prepared directly from asuitably protected PEG-amine by deprotecting said protected amine withan acid. Accordingly, in other embodiments, the terminating agent hassuitably protected amino group wherein the protecting group isacid-labile.

Alternatively, suitable synthetic polymers having a terminal amine saltmay be prepared from synthetic polymers that contain terminal functionalgroups that may be converted to amine salts by known synthetic routes.In certain embodiments, the conversion of the terminal functional groupsto the amine salts is conducted in a single synthetic step. In otherembodiments, the conversion of the terminal functional groups to theamine salts is achieved by way of a multi-step sequence. Functionalgroup transformations that afford amines, amine salts, or protectedamines are well known in the art and include those described in Larock,R. C., “Comprehensive Organic Transformations,” John Wiley & Sons, NewYork, 1999.

At step (a), the polymerization initiator is treated with a suitablebase to form D. A variety of bases are suitable for the reaction at step(a). Such bases include, but are not limited to, potassiumnaphthalenide, diphenylmethyl potassium, triphenylmethyl potassium, andpotassium hydride. At step (b), the resulting anion is treated withethylene oxide to form the polymer E. Polymer E can be transformed atstep (d) to a compound of formula A directly by terminating the livingpolymer chain-end of E with a suitable polymerization terminator toafford a compound of formula A. Alternatively, polymer E may be quenchedat step (c) to form the hydroxyl compound F. Compound F is thenderivatized to afford a compound of formula A by methods known in theart, including those described herein. Each of the R², L¹, A, y, and Qgroups depicted in Scheme 2 are as defined and described in classes andsubclasses, singly and in combination, herein.

Although certain exemplary embodiments are depicted and described aboveand herein, it will be appreciated that compounds of the invention canbe prepared according to the methods described generally above usingappropriate starting materials by methods generally available to one ofordinary skill in the art. Additional embodiments are exemplified inmore detail herein.

5. Uses

The modified metal surfaces in accordance with the present invention areuseful for a multitude of uses. In certain embodiments, the covalentlymodified metal surfaces are useful in any application where metal istypically coated in a non-covalent fashion. Such applications includecoated implantable medical devices. Such implantable devices includeprostheses, artificial valves, vascular grafts, stents, catheters, andthe like. These, and other such devices, are described in more detailbelow. In certain embodiments, the implantable device is acardiovascular device, a neurosurgical device, a gastrointestinaldevice, a genitourinary device, a phthalmologic implant, anotolaryngology device, a plastic surgery implant, or an orthopedicimplant.

Certain disorders are associated with the tissue trauma resulting from amedical procedure, such as angioplasty, or from the implantation of amedical device. For example, restenosis is a re-narrowing or blockage ofan artery at the same site where treatment, such as an angioplasty orstent procedure, has already taken place. One cause of restenosis istissue growth at the site of treatment characterized by a proliferationof the smooth muscle cells that normally line blood vessels.

Recent developments in the ongoing battle to reduce restenosis includethe drug-eluting stent which has a medication coated on it to reduce theproliferation of cells that can cause restenosis. There is a continuingneed to develop stents and other implantable devices coated withanti-proliferative agents advantageous for treating or preventingdisorders associated with tissue trauma caused by implantable devices.

According to another aspect, the present invention provides a method fortreating or preventing disorders associated with tissue trauma caused byimplantable devices wherein said method comprises providing animplantable device, wherein at least a portion of said implantabledevice is a covalently modified metal surface in accordance with thepresent invention, and implanting said device in a patient. Said methodis useful for treating or preventing, for example, restenosis of bloodvessels subject to traumas such as angioplasty and stenting.

In other embodiments, the present invention provides an implantabledevice, wherein at least a portion of said device is a covalentlymodified metal surface. In still other embodiments, the presentinvention provides a PEGylated implantable device, wherein at least aportion of said device is a metal surface comprising PEG covalentlybonded thereto.

Vascular stents, for example, have been used to overcome restenosis(re-narrowing of the vessel wall after injury). However, patients usingstents or other implantable devices risk clot formation or plateletactivation. These unwanted effects may be prevented or mitigated bypre-coating the device with a composition comprising ananti-proliferative compound. Such coatings and the general preparationof coated implantable devices are described in U.S. Pat. Nos. 6,099,562;5,886,026; and 5,304,121. The coatings are typically biocompatiblepolymeric materials such as a hydrogel polymer, polymethyldisiloxane,polycaprolactone, polyethylene glycol, polylactic acid, ethylene vinylacetate, and mixtures thereof. However, none of these coatings iscovalently bonded to the device.

As described generally herein, one method of treating restenosis is tocoat an implantable device with an anti-proliferative compound. Althoughthe present invention contemplates covalently modified metal surfaceswhich incorporate small molecule drugs, one of ordinary skill in the artwill appreciate that the present invention also contemplates covalentlymodified metal surfaces which do not incorporate small molecule drugs.Without wishing to be bound by any particular theory, it is believedthat the “stealth” properties of PEG are particularly suited forimplantable devices having at least a portion which is a metal surfacecovalently modified with PEG or a functionalized PEG. It is believedthat the PEG itself will not induce restenosis, or other tissue injurycaused by an implantable device, thereby negating the need forincorporation of an anti-proliferative or other small molecule drug.Thus, the present invention also provides an implantable devicecovalently modified in accordance with the present invention. In certainembodiments, the implantable device is covalently modified by afunctionalized PEG. In other embodiments, the implantable device iscovalently modified by a functionalized PEG of formula II as definedabove and in classes and subclasses described herein.

As discussed above, the present devices are useful for treating orpreventing restenosis of blood vessels subject to traumas such asangioplasty and stenting. For example, it is contemplated that suchimplanted medical devices include as tubings, shunts, catheters,artificial implants, pins, electrical implants such as pacemakers, andespecially for arterial or venous stents, including balloon-expandablestents.

In certain embodiments, methods of the present invention are used forcoating stents, or a metallic substrate to be made into a stent. A stentis typically an open tubular structure that has a pattern (or patterns)of apertures extending from the outer surface of the stent to the lumen.It is commonplace to make stents of biocompatible metallic materials,with the patterns cut on the surface with a laser machine. The stent canbe electro-polished to minimize surface irregularities since theseirregularities can trigger an adverse biological response. However,stents may still stimulate foreign body reactions that result inthrombosis or restenosis. To avoid these complications, a variety ofstent coatings and compositions have been proposed to reduce theincidence of these complications or other complications and restoretissue function by itself or by delivering therapeutic compound to thelumen. For example, compounds having antiproliferative andanti-inflammatory activities have been evaluated as stent coatings, andhave shown promise in preventing restenosis (See, for example,Presbitero P. et al., “Drug eluting stents do they make thedifference?”, Minerva Cardioangiol, 2002, 50(5):431-442; Ruygrok P. N.et al., “Rapamycin in cardiovascular medicine”, Intern. Med. J., 2003,33(3):103-109; and Marx S. O. et al., “Bench to bedside: the developmentof rapamycin and its application to stent restenosis”, Circulation,2001, 104(8):852-855).

In certain embodiments, the present invention provides a stent, havingat least a portion which is a covalently modified metal surface, forinsertion into an artery or vein following balloon angioplasty.According to one aspect, the present invention provides a method ofinhibiting arterial restenosis or arterial occlusion following vasculartrauma comprising insertion into a subject in need thereof, a stent,having at least a portion which is a covalently modified metal surface.In the practice of the method, the subject may be a coronary bypass,vascular surgery, organ transplant or coronary or any other arterialangioplasty patient, for example.

In another aspect, the invention encompasses implants and surgical ormedical devices, including stents and grafts, having at least a portionwhich is a covalently modified metal surface. In certain embodiments,the devices include compounds which inhibit smooth muscle cellproliferation. Representative examples of implants and surgical ormedical devices contemplated by the present invention includecardiovascular devices (e.g., implantable venous catheters, venousports, tunneled venous catheters, chronic infusion lines or ports,including hepatic artery infusion catheters, pacemaker wires,implantable defibrillators); neurologic/neurosurgical devices (e.g.,ventricular peritoneal shunts, ventricular atrial shunts, nervestimulator devices, dural patches and implants to prevent epiduralfibrosis post-laminectomy, devices for continuous subarachnoidinfusions); gastrointestinal devices (e.g., chronic indwellingcatheters, feeding tubes, portosystemic shunts, shunts for ascites,peritoneal implants for drug delivery, peritoneal dialysis catheters,implantable meshes for hernias, suspensions or solid implants to preventsurgical adhesions, including meshes); genitourinary devices (e.g.,uterine implants, including intrauterine devices (IUDs) and devices toprevent endometrial hyperplasia, fallopian tubal implants, includingreversible sterilization devices, fallopian tubal stents, artificialsphincters and periurethral implants for incontinence, ureteric stents,chronic indwelling catheters, bladder augmentations, or wraps or splintsfor vasovasostomy); otolaryngology devices (e.g., ossicular implants,Eustachian tube splints or stents for glue ear or chronic otitis as analternative to transtempanic drains); and orthopedic implants (e.g.,cemented orthopedic prostheses).

In other embodiments of the invention, the implant or devicecontemplated by the present invention provides a uniform, predictable,prolonged release of the therapeutic agent, or composition thereof, intothe tissue surrounding the implant or device once it has been deployed.For vascular stents, in addition to the above properties, thecomposition should not render the stent thrombogenic (causing bloodclots to form), or cause significant turbulence in blood flow (more thanthe stent itself would be expected to cause if it was uncoated). Incertain embodiments, said therapeutic agent is an anti-proliferativecompound. In still other embodiments, said therapeutic agent isPaclitaxel.

In the case of stents, a wide variety of stents may be covalentlymodified in accordance with the present invention including esophagealstents, gastrointestinal stents, vascular stents, biliary stents,colonic stents, pancreatic stents, ureteric and urethral stents,lacrimal stents, Eustachian tube stents, fallopian tube stents andtracheal/bronchial stents (See, for example, U.S. Pat. No. 6,515,016,the entire contents of which are incorporated herein by reference).Stents may be readily obtained from commercial sources, or constructedin accordance with well-known techniques. Representative examples ofstents include those described in U.S. Pat. No. 4,768,523, entitled“Hydrogel Adhesive”; U.S. Pat. No. 4,776,337, entitled “ExpandableIntraluminal Graft, and Method and Apparatus for Implanting andExpandable Intraluminal Graft”; U.S. Pat. No. 5,041,126 entitled“Endovascular Stent and Delivery System”; U.S. Pat. No. 5,052,998entitled “Indwelling Stent and Method of Use”; U.S. Pat. No. 5,064,435entitled “Self-Expanding Prosthesis Having Stable Axial Length”; U.S.Pat. No. 5,147,370, entitled “Nitinol Stent for Hollow Body Conduits”;U.S. Pat. No. 5,176,626, entitled “Indwelling Stent”; U.S. Pat. No.6,344,028 entitled “Replenishable Stent and Delivery System”; and U.S.Pat. No. 5,328,471, entitled “Method and Apparatus for Treatment ofFocal Disease in Hollow Tubular Organs and Other Tissue Lumens.”

As discussed above, the stent covalently modified in accordance with thepresent invention may be used to eliminate a vascular obstruction andprevent restenosis or reduce the rate of restenosis. Within otheraspects of the present invention, such stents are provided for expandingthe lumen of a body passageway. Specifically, a stent having a generallytubular structure, and at least a portion which is covalently modifiedmetal, may be inserted into the passageway, such that the passageway isexpanded. In certain embodiments, the stent may be used to eliminate abiliary, gastrointestinal, esophageal, tracheal/bronchial, urethral orvascular obstruction.

In other embodiments, methods are provided for preventing restenosis,comprising inserting a stent into an obstructed blood vessel, the stenthaving a generally tubular structure, at least a portion of the surfaceof the structure being covalently modified in accordance with thepresent invention, such that the obstruction is eliminated and smoothmuscle cell proliferation is prevented or inhibited.

Within other aspects of the present invention, methods are provided forexpanding the lumen of a body passageway, comprising inserting a stentinto the passageway, the stent having a generally tubular structure, atleast a portion of the surface of the structure being covalentlymodified in accordance with the present invention, such that thepassageway is expanded. In certain embodiments, the lumen of a bodypassageway is expanded in order to eliminate a biliary,gastrointestinal, esophageal, tracheal/bronchial, urethral and/orvascular obstruction.

In certain embodiments, methods are provided for eliminating biliaryobstructions, comprising inserting a biliary stent into a biliarypassageway, the stent having a generally tubular structure, at least aportion of the surface of the structure being covalently modified inaccordance with the present invention, such that the biliary obstructionis eliminated. For example, tumor overgrowth of the common bile ductresults in progressive cholestatic jaundice which is incompatible withlife. Generally, the biliary system which drains bile from the liverinto the duodenum is most often obstructed by (1) a tumor composed ofbile duct cells (cholangiocarcinoma), (2) a tumor which invades the bileduct (e.g., pancreatic carcinoma), or (3) a tumor which exerts extrinsicpressure and compresses the bile duct (e.g., enlarged lymph nodes). Bothprimary biliary tumors, as well as other tumors which cause compressionof the biliary tree may be treated utilizing stents, implants and othersurgical or medical devices, at least a portion of which is metal whichis covalently modified in accordance with the present invention.

One example of primary biliary tumors are adenocarcinomas (which arealso called Klatskin tumors when found at the bifurcation of the commonhepatic duct). These tumors are also referred to as biliary carcinomas,choledocholangiocarcinomas, or adenocarcinomas of the biliary system.Benign tumors which affect the bile duct (e.g., adenoma of the biliarysystem), and, in rare cases, squamous cell carcinomas of the bile ductand adenocarcinomas of the gallbladder, may also cause compression ofthe biliary tree and therefore, result in biliary obstruction.Compression of the biliary tree is most commonly due to tumors of theliver and pancreas which compress and therefore obstruct the ducts. Mostof the tumors from the pancreas arise from cells of the pancreaticducts. This is a highly fatal form of cancer (5% of all cancer deaths;26,000 new cases per year in the U.S.) with an average of 6 monthssurvival and a 1 year survival rate of only 10%. When these tumors arelocated in the head of the pancreas they frequently cause biliaryobstruction, and this detracts significantly from the quality of life ofthe patient. While all types of pancreatic tumors are generally referredto as “carcinoma of the pancreas” there are histologic subtypesincluding: adenocarcinoma, adenosquamous carcinoma, cystadenocarcinoma,and acinar cell carcinoma. Hepatic tumors, as discussed above, may alsocause compression of the biliary tree, and therefore cause obstructionof the biliary ducts.

A biliary stent is first inserted into a biliary passageway in one ofseveral ways: from the top end by inserting a needle through theabdominal wall and through the liver (a percutaneous transhepaticcholangiogram or “PTC”); from the bottom end by cannulating the bileduct through an endoscope inserted through the mouth, stomach, andduodenum (an endoscopic retrograde cholangiogram or “ERCP”); or bydirect incision during a surgical procedure. A preinsertion examination,PTC, ERCP, or direct visualization at the time of surgery is optionallyperformed to determine the appropriate position for stent insertion. Aguidewire is then advanced through the lesion, and over this a deliverycatheter is passed to allow the stent to be inserted in its collapsedform. If the diagnostic exam was a PTC, the guidewire and deliverycatheter is inserted via the abdominal wall, while if the original examwas an ERCP the stent may be placed via the mouth. The stent is thenpositioned under radiologic, endoscopic, or direct visual control takingparticular care to place it precisely across the narrowing in the bileduct. The delivery catheter is then removed leaving the stent standingas a scaffolding which holds the bile duct open. A further cholangiogrammay be performed to document that the stent is appropriately positioned.

In certain embodiments, methods are provided for eliminating esophagealobstructions, comprising inserting an esophageal stent into anesophagus, the stent having a generally tubular structure, at least aportion of the surface of the structure being covalently modified inaccordance with the present invention, such that the esophagealobstruction is eliminated. For example, the esophagus is the hollow tubewhich transports food and liquids from the mouth to the stomach. Cancerof the esophagus or invasion by cancer arising in adjacent organs (e.g.,cancer of the stomach or lung) results in the inability to swallow foodor saliva. In certain embodiments, a pre-insertion examination, usuallya barium swallow or endoscopy is performed in order to determine theappropriate position for stent insertion. A catheter or endoscope maythen be positioned through the mouth, and a guidewire is advancedthrough the blockage. A stent delivery catheter is passed over theguidewire under radiologic or endoscopic control, and a stent is placedprecisely across the narrowing in the esophagus. A post-insertionexamination, usually a barium swallow x-ray, may be utilized to confirmappropriate positioning.

In certain embodiments, methods are provided for eliminating colonicobstructions, comprising inserting a colonic stent into a colon, thestent having a generally tubular structure, at least a portion of thesurface of the structure being covalently modified in accordance withthe present invention, such that the colonic obstruction is eliminated.For example, the colon is the hollow tube which transports digested foodand waste materials from the small intestines to the anus. Cancer of therectum and/or colon or invasion by cancer arising in adjacent organs(e.g., cancer of the uterus, ovary, bladder) results in the inability toeliminate feces from the bowel. In certain embodiments, a pre-insertionexamination, usually a barium enema or colonoscopy is performed in orderto determine the appropriate position for stent insertion. A catheter orendoscope may then be positioned through the anus, and a guidewire isadvanced through the blockage. A stent delivery catheter is passed overthe guidewire under radiologic or endoscopic control, and a stent isplaced precisely across the narrowing in the colon or rectum. Apost-insertion examination, usually a barium enema x-ray, may beutilized to confirm appropriate positioning.

In certain embodiments, methods are provided for eliminatingtracheal/bronchial obstructions, comprising inserting atracheal/bronchial stent into a trachea or bronchi, the stent having agenerally tubular structure, at least a portion of the surface of thestructure being covalently modified in accordance with the presentinvention, such that the tracheal/bronchial obstruction is eliminated.For example, the trachea and bronchi are tubes which carry air from themouth and nose to the lungs. Blockage of the trachea by cancer, invasionby cancer arising in adjacent organs (e.g., cancer of the lung), orcollapse of the trachea or bronchi due to chondromalacia (weakening ofthe cartilage rings) results in inability to breathe. In certainembodiments, a pre-insertion examination, usually an endoscopy, isperformed in order to determine the appropriate position for stentinsertion. A catheter or endoscope is then positioned through the mouth,and a guidewire advanced through the blockage. A delivery catheter isthen passed over the guidewire in order to allow a collapsed stent to beinserted. The stent is placed under radiologic or endoscopic control inorder to place it precisely across the narrowing. The delivery cathetermay then be removed leaving the stent standing as a scaffold on its own.A post-insertion examination, usually a bronchoscopy may be utilized toconfirm appropriate positioning.

In certain embodiments, methods are provided for eliminating urethralobstructions, comprising inserting a urethral stent into a urethra, thestent having a generally tubular structure, at least a portion of thesurface of the structure being covalently modified in accordance withthe present invention, such that the urethral obstruction is eliminated.For example, the urethra is the tube which drains the bladder throughthe penis. Extrinsic narrowing of the urethra as it passes through theprostate, due to hypertrophy of the prostate, occurs in virtually everyman over the age of 60 and causes progressive difficulty with urination.In certain embodiments, a pre-insertion examination, usually anendoscopy or urethrogram is first performed in order to determine theappropriate position for stent insertion, which is above the externalurinary sphincter at the lower end, and close to flush with the bladderneck at the upper end. An endoscope or catheter is then positionedthrough the penile opening and a guidewire advanced into the bladder. Adelivery catheter is then passed over the guidewire in order to allowstent insertion. The delivery catheter is then removed, and the stentexpanded into place. A post-insertion examination, usually endoscopy orretrograde urethrogram, may be utilized to confirm appropriate position.

In certain embodiments, methods are provided for eliminating vascularobstructions, comprising inserting a vascular stent into a blood vessel,the stent having a generally tubular structure, at least a portion ofthe surface of the structure being covalently modified in accordancewith the present invention, such that the vascular obstruction iseliminated. For example, stents may be placed in a wide array of bloodvessels, both arteries and veins, to prevent recurrent stenosis at thesite of failed angioplasties, to treat narrowings that would likely failif treated with angioplasty, and to treat post-surgical narrowings(e.g., dialysis graft stenosis). Suitable sites include, but are notlimited to, the iliac, renal, and coronary arteries, the superior venacava, and in dialysis grafts. In certain embodiments, angiography isfirst performed in order to localize the site for placement of thestent. This is typically accomplished by injecting radiopaque contrastthrough a catheter inserted into an artery or vein as an x-ray is taken.A catheter may then be inserted either percutaneously or by surgery intothe femoral artery, brachial artery, femoral vein, or brachial vein, andadvanced into the appropriate blood vessel by steering it through thevascular system under fluoroscopic guidance. A stent may then bepositioned across the vascular stenosis. A post-insertion angiogram mayalso be utilized in order to confirm appropriate positioning.

Compositions comprising one or more therapeutic agents can be coated ona device according to the present invention, which is then implanted toprovide localized delivery of the therapeutic agent or agents containedtherein. In certain embodiments, said therapeutic agent is ananti-proliferative compound. In still other embodiments, saidtherapeutic agent is Paclitaxel. General methods for delivering thetherapeutic agent or agents contained within the coating on said deviceto targeted areas of the body have been described, for example, in U.S.Pat. No. 5,651,986. Such localized delivery is useful for, among otherthings, inhibiting the growth of a tumor. This method avoids thesystemic levels of the chemotherapeutic agent or agents often associatedwith toxicity. The localized delivery of the therapeutic agent isachieved by implanting a device, coated with a composition of thepresent invention, proximally to the tumor. The therapeutic agent istypically released from the device by diffusion, degradation of thematrix, or a combination thereof. Thus, another aspect of the presentinvention relates to a method for inhibiting growth of a tumor, in apatient in need thereof, comprising implanting a device, coated with acomposition as described herein, for administering localized delivery ofthe therapeutic agent.

EXAMPLES Preparation of Bifunctional PEGs and Multiblock Copolymers ofthe Present Invention

As described generally above, multiblock copolymers of the presentinvention are prepared using the heterobifunctional PEGs describedherein and in United States patent application publication numberUS20060142506, the entirety of which is hereby incorporated herein byreference. The preparation of multiblock polymers in accordance with thepresent invention is accomplished by methods known in the art, includingthose described in detail in United States patent applicationpublication number US20060172914, the entirety of which is herebyincorporated herein by reference.

Example 1

A coupon of 316 stainless steel is placed in an oxidation reactor andtreated with a 1.3×10¹⁶ m⁻³ and 3 eV water vapor plasma at 100° C. for aperiod of 24 hours. The metal substrate is placed in an aqueous solutioncontaining 5 wt % phosphonic acid functionalized poly(ethylene glycol)for one hour. The substrate is removed from the PEG solution and driedunder vacuum at 160° C. for 24 hours to give the desiredPEG-functionalized stainless steel. See FIG. 11.

Example 2

A ½″×½″×⅛″ 316 L stainless steel coupon was cleaned with an argon plasmaprocess (250 mtorr Ar₂, 100° C., 4000 watts for 15 minutes at a flow of2.5 slm). The freshly cleaned coupon was then exposed to an oxygenplasma treatment (250 mtorr O₂, 100° C., 4000 watts for 15 minutes flowof 2.5 slm). Contact angle was found to be 8°.

Example 3

A coupon of 316 stainless steel is placed in an oxidation reactor andtreated with a 1.3×10¹⁶ m⁻³ and 3 eV water vapor plasma at 100° C. for aperiod of 24 hours. The metal substrate is placed in a vacuum flask andthe system evacuated. The flask is backfilled with Argon and ananhydrous solution containing 5 wt % phosphonic chloride functionalizedpoly(ethylene glycol) in tetrahydrofuran is added. After sixteen hours,the substrate is removed from the PEG solution and dried under vacuum at60° C. for 24 hours to give the desired PEG-functionalized stainlesssteel. See FIG. 12.

Example 4

An oxygen plasma treated coupon was placed in an aqueous solutioncontaining 10 wt % THP-PEG-Phosphonic acid (5,000 g/mol). The coupon wasallowed to remain in the PEG solution for 2 hours at which point it wasremoved for the PEG solution and placed in a pyrex dish. The coupon washeated to 160° C. under vacuum for 12 hours. The coupon was allowed tocool to room temperature at which point is was washed with methylenechloride and acetone and subsequently dried with a paper towel. Contactangle was found to be 18°.

Example 5

An oxygen plasma treated coupon was placed in an aqueous solutioncontaining 10 wt % dibenzylamine-PEG-Phosphonic acid (8,000 g/mol). Thecoupon was allowed to remain in the PEG solution for 2 hours at whichpoint it was removed for the PEG solution and placed in a pyrex dish.The coupon was heated to 160° C. under vacuum for 12 hours. The couponwas allowed to cool to room temperature at which point is was washedwith methylene chloride and acetone and subsequently dried with a papertowel. Contact angle was found to be 49°.

1.-15. (canceled)
 16. A compound of formula II-e:

or a salt thereof, wherein: W is —C(═O)OH, —C(═O)X, —P(═O)(OH)₂,—P(═O)(X)₂, —P(═O)(R^(a))OH, —P(═O)(R^(a))X, —Si(R^(a))₂OH,—Si(OR^(a))₂OH, —Si(R^(a))₂X, —Si(R^(a))(OH)₂, —Si(R^(a))X₂,—Si(OR^(a))₂X, or N═C═O; each X is independently Cl, Br, or I; and eachR^(a) is hydrogen, an alkyl group, or an aryl group; y is 1-2500; each Ris independently hydrogen or an optionally substituted aliphatic group;L¹ is a valence bond or a bivalent, saturated or unsaturated, straightor branched C₁₋₁₂ alkylene chain, wherein 0-6 methylene units of L¹ areindependently replaced by -Cy-, —O—, —NR—, —S—, —OC(O)—, —C(O)O—,—C(O)—, —SO—, —SO₂—, —NRSO₂—, —SO₂NR—, —NRC(O)—, —C(O)NR—, —OC(O)NR—, or—NRC(O)O—, wherein: each -Cy- is independently an optionally substituted3-8 membered bivalent, saturated, partially unsaturated, or aryl ringhaving 0-4 heteroatoms independently selected from nitrogen, oxygen, orsulfur, or an optionally substituted 8-10 membered bivalent saturated,partially unsaturated, or aryl bicyclic ring having 0-5 heteroatomsindependently selected from nitrogen, oxygen, or sulfur; and L² is avalence bond or a bivalent, saturated or unsaturated, straight orbranched C₁₋₁₂ alkylene chain, wherein 0-6 methylene units of L² areindependently replaced by -Cy-, —O—, —NR—, —S—, or —C(O)—, wherein: each-Cy- is independently an optionally substituted 3-8 membered bivalent,saturated, partially unsaturated, or aryl ring having 0-4 heteroatomsindependently selected from nitrogen, oxygen, or sulfur, or anoptionally substituted 8-10 membered bivalent saturated, partiallyunsaturated, or aryl bicyclic ring having 0-5 heteroatoms independentlyselected from nitrogen, oxygen, or sulfur.
 17. An implantable device,wherein at least a portion of said device is a covalently modified metalsurface.
 18. The implantable device according to claim 17, wherein saiddevice is PEGylated.
 19. The implantable device according to claim 17,wherein said device is selected from cardiovascular devices (e.g.,implantable venous catheters, venous ports, tunneled venous catheters,chronic infusion lines or ports, including hepatic artery infusioncatheters, pacemaker wires, implantable defibrillators);neurologic/neurosurgical devices (e.g., ventricular peritoneal shunts,ventricular atrial shunts, nerve stimulator devices, dural patches andimplants to prevent epidural fibrosis post-laminectomy, devices forcontinuous subarachnoid infusions); gastrointestinal devices (e.g.,chronic indwelling catheters, feeding tubes, portosystemic shunts,shunts for ascites, peritoneal implants for drug delivery, peritonealdialysis catheters, implantable meshes for hernias, suspensions or solidimplants to prevent surgical adhesions, including meshes); genitourinarydevices (e.g., uterine implants, including intrauterine devices (IUDs)and devices to prevent endometrial hyperplasia, fallopian tubalimplants, including reversible sterilization devices, fallopian tubalstents, artificial sphincters and periurethral implants forincontinence, ureteric stents, chronic indwelling catheters, bladderaugmentations, or wraps or splints for vasovasostomy); otolaryngologydevices (e.g., ossicular implants, Eustachian tube splints or stents forglue ear or chronic otitis as an alternative to transtempanic drains);and orthopedic implants (e.g., cemented orthopedic prostheses).
 20. Theimplantable device according to claim 19, wherein said device is astent.
 21. A method for expanding the lumen of a body passageway,comprising inserting a stent into the passageway, the stent having agenerally tubular structure, at least a portion of the surface of thestructure being covalently modified according to the method of claim 1,such that the passageway is expanded.